diff --git a/library/src/main/java/com/billing/BillingService.kt b/library/src/main/java/com/billing/BillingService.kt
index dd181d4..fd49e73 100644
--- a/library/src/main/java/com/billing/BillingService.kt
+++ b/library/src/main/java/com/billing/BillingService.kt
@@ -1,6 +1,8 @@
 package com.billing
 
 import android.app.Activity
+import android.os.Handler
+import android.os.Looper
 import androidx.annotation.CallSuper
 
 abstract class BillingService {
@@ -29,6 +31,12 @@ abstract class BillingService {
      * @param isRestore - a flag indicating whether it's a fresh purchase or restored product
      */
     fun productOwned(sku: String?, isRestore: Boolean) {
+        findUiHandler().post {
+            productOwnedInternal(sku, isRestore)
+        }
+    }
+
+    fun productOwnedInternal(sku: String?, isRestore: Boolean) {
         for (purchaseServiceListener in purchaseServiceListeners) {
             if (isRestore) {
                 purchaseServiceListener.onProductRestored(sku)
@@ -43,6 +51,12 @@ abstract class BillingService {
      * @param isRestore - a flag indicating whether it's a fresh purchase or restored subscription
      */
     fun subscriptionOwned(sku: String, isRestore: Boolean) {
+        findUiHandler().post {
+            subscriptionOwnedInternal(sku, isRestore)
+        }
+    }
+
+    fun subscriptionOwnedInternal(sku: String, isRestore: Boolean) {
         for (subscriptionServiceListener in subscriptionServiceListeners) {
             if (isRestore) {
                 subscriptionServiceListener.onSubscriptionRestored(sku)
@@ -53,6 +67,12 @@ abstract class BillingService {
     }
 
     fun updatePrices(iapkeyPrices: Map<String, String>) {
+        findUiHandler().post {
+            updatePricesInternal(iapkeyPrices)
+        }
+    }
+
+    fun updatePricesInternal(iapkeyPrices: Map<String, String>) {
         for (billingServiceListener in purchaseServiceListeners) {
             billingServiceListener.onPricesUpdated(iapkeyPrices)
         }
@@ -72,4 +92,8 @@ abstract class BillingService {
         subscriptionServiceListeners.clear()
         purchaseServiceListeners.clear()
     }
+}
+
+fun findUiHandler(): Handler {
+    return Handler(Looper.getMainLooper())
 }
\ No newline at end of file
diff --git a/library/src/test/java/com/eggheadgames/inapppayments/BillingTest.java b/library/src/test/java/com/eggheadgames/inapppayments/BillingTest.java
index fa14237..1f802d4 100644
--- a/library/src/test/java/com/eggheadgames/inapppayments/BillingTest.java
+++ b/library/src/test/java/com/eggheadgames/inapppayments/BillingTest.java
@@ -31,7 +31,7 @@ public void onProductOwnedEvent_eachRegisteredListenerShouldBeTriggered() throws
         PurchaseServiceListener secondListener = Mockito.spy(PurchaseServiceListener.class);
         IAPManager.addPurchaseListener(secondListener);
 
-        IAPManager.getBillingService().productOwned(TestConstants.TEST_SKU, false);
+        IAPManager.getBillingService().productOwnedInternal(TestConstants.TEST_SKU, false);
 
         Mockito.verify(firstListener, Mockito.times(1)).onProductPurchased(TestConstants.TEST_SKU);
         Mockito.verify(secondListener, Mockito.times(1)).onProductPurchased(TestConstants.TEST_SKU);
@@ -51,7 +51,7 @@ public void onProductDetailsFetched_eachRegisteredListenerShouldBeTriggered() {
         products.put(TestConstants.TEST_SKU, TestConstants.TEST_PRODUCT);
         products.put(TestConstants.TEST_SKU_1, TestConstants.TEST_PRODUCT);
 
-        IAPManager.getBillingService().updatePrices(products);
+        IAPManager.getBillingService().updatePricesInternal(products);
 
         Mockito.verify(firstListener, Mockito.times(1)).onPricesUpdated(products);
         Mockito.verify(secondListener, Mockito.times(1)).onPricesUpdated(products);
@@ -69,7 +69,7 @@ public void onIapManagerInteraction_onlyRegisteredListenersShouldBeTriggered() {
 
         IAPManager.removePurchaseListener(firstListener);
 
-        IAPManager.getBillingService().productOwned(TestConstants.TEST_SKU, false);
+        IAPManager.getBillingService().productOwnedInternal(TestConstants.TEST_SKU, false);
 
         Mockito.verify(firstListener, Mockito.never()).onProductPurchased(Mockito.anyString());
         Mockito.verify(secondListener, Mockito.times(1)).onProductPurchased(TestConstants.TEST_SKU);
@@ -83,7 +83,7 @@ public void onProductPurchase_purchaseCallbackShouldBeTriggered() {
         PurchaseServiceListener listener = Mockito.spy(PurchaseServiceListener.class);
         IAPManager.addPurchaseListener(listener);
 
-        IAPManager.getBillingService().productOwned(TestConstants.TEST_SKU, false);
+        IAPManager.getBillingService().productOwnedInternal(TestConstants.TEST_SKU, false);
 
         Mockito.verify(listener, Mockito.times(1)).onProductPurchased(TestConstants.TEST_SKU);
     }
@@ -95,7 +95,7 @@ public void onProductRestore_restoreCallbackShouldBeTriggered() {
         PurchaseServiceListener listener = Mockito.spy(PurchaseServiceListener.class);
         IAPManager.addPurchaseListener(listener);
 
-        IAPManager.getBillingService().productOwned(TestConstants.TEST_SKU, true);
+        IAPManager.getBillingService().productOwnedInternal(TestConstants.TEST_SKU, true);
 
         Mockito.verify(listener, Mockito.times(1)).onProductRestored(TestConstants.TEST_SKU);
     }
@@ -107,7 +107,7 @@ public void onSubscriptionPurchase_purchaseCallbackShouldBeTriggered() {
         SubscriptionServiceListener listener = Mockito.spy(SubscriptionServiceListener.class);
         IAPManager.addSubscriptionListener(listener);
 
-        IAPManager.getBillingService().subscriptionOwned(TestConstants.TEST_SKU, false);
+        IAPManager.getBillingService().subscriptionOwnedInternal(TestConstants.TEST_SKU, false);
 
         Mockito.verify(listener, Mockito.times(1)).onSubscriptionPurchased(TestConstants.TEST_SKU);
     }
@@ -119,7 +119,7 @@ public void onSubscriptionRestore_restoreCallbackShouldBeTriggered() {
         SubscriptionServiceListener listener = Mockito.spy(SubscriptionServiceListener.class);
         IAPManager.addSubscriptionListener(listener);
 
-        IAPManager.getBillingService().subscriptionOwned(TestConstants.TEST_SKU, true);
+        IAPManager.getBillingService().subscriptionOwnedInternal(TestConstants.TEST_SKU, true);
 
         Mockito.verify(listener, Mockito.times(1)).onSubscriptionRestored(TestConstants.TEST_SKU);
     }