ProcessPurchase not working 4.12.2

In android build in testing, when I click on button to buy subscription, I am able to get overlay and successfully buy it in testing but ProcessPurchase is not called/Debug statements inside it are not shown. Please let me know what I am doing wrong? It works if I uninstall and its automatically restores purchase.

public GooglePlayProrationMode upgradeSubscriptionProrationMode = GooglePlayProrationMode.ImmediateAndChargeProratedPrice;
        public GooglePlayProrationMode downgradeSubscriptionProrationMode = GooglePlayProrationMode.ImmediateAndChargeProratedPrice;

        // public Text currentSubscriptionText;
        // public Text deferredSubscriptionChangeText;
        #if UNITY_ANDROID
        GoogleSubscriptionGroup m_SubscriptionGroup;
        #endif
        #if UNITY_IOS
        AppleSubscriptionGroup m_SubscriptionGroup;
        #endif

        public void CatalogInit()
        {
            InitializePurchasing();
        }

        void InitializePurchasing()
        {
            var builder = ConfigurationBuilder.Instance(StandardPurchasingModule.Instance());

            //When a subscription change has the DEFERRED proration mode, the subscription is upgraded or downgraded only when the subscription renews.
            //This sets a listener for when the subscription change is requested but hasn't occured yet.
            //We notify the user that the subscription change will take effect at the next renewal cycle.

            #if UNITY_ANDROID
            builder.Configure<IGooglePlayConfiguration>()
                .SetDeferredProrationUpgradeDowngradeSubscriptionListener(NotifyUserOfOnDeferredSubscriptionChange);
            #endif

            // builder.AddProduct(normalSubscriptionId, ProductType.Subscription);
            // builder.AddProduct(vipSubscriptionId, ProductType.Subscription);

            builder.AddProduct(premium1Month, ProductType.Subscription);
            builder.AddProduct(premium6Month, ProductType.Subscription);
            builder.AddProduct(premium12Month, ProductType.Subscription);

            builder.AddProduct(premiumPlus1Month, ProductType.Subscription);
            builder.AddProduct(premiumPlus6Month, ProductType.Subscription);
            builder.AddProduct(premiumPlus12Month, ProductType.Subscription);

            UnityPurchasing.Initialize(this, builder);
        }

        void NotifyUserOfOnDeferredSubscriptionChange(Product product)
        {
            var msg = $"Subscription change to {product.definition.id} is deferred until the next renewal cycle.";
            Debug.Log(msg);
        }

        public void OnInitialized(IStoreController controller, IExtensionProvider extensions)
        {
            Debug.Log("In-App Purchasing successfully initialized");
            #if UNITY_ANDROID
                m_SubscriptionGroup = new GoogleSubscriptionGroup(controller, extensions, upgradeSubscriptionProrationMode, downgradeSubscriptionProrationMode,
                    premium1Month,premium6Month,premium12Month,premiumPlus1Month,premiumPlus6Month,premiumPlus12Month);
            #elif UNITY_IOS 
                m_AppleExtensions = extensions.GetExtension<IAppleExtensions>();
                m_AppleExtensions.RegisterPurchaseDeferredListener(NotifyUserOfOnDeferredSubscriptionChange);
                m_SubscriptionGroup = new AppleSubscriptionGroup(controller, extensions, premium1Month,premium6Month,premium12Month,premiumPlus1Month,premiumPlus6Month,premiumPlus12Month);
            #else
                Debugx.Log("Unsupported Platform");
            #endif

            Debug.Log($"CurrentSubscription {m_SubscriptionGroup.CurrentSubscriptionId()}");
            // UpdateUI(m_SubscriptionGroup.CurrentSubscriptionId());
        }

        public void BuyNormalSubscription()
        {
            m_SubscriptionGroup.BuySubscription(premium1Month);
        }

        public void BuyVipSubscription()
        {
            m_SubscriptionGroup.BuySubscription(premiumPlus1Month);
        }




        public PurchaseProcessingResult ProcessPurchase(PurchaseEventArgs args)
        {
            var product = args.purchasedProduct;

            Debug.Log($"Actually buying Processing Purchase: {product.definition.id}");
            // Debug.Log($"Reciept : {product.transactionID}");

            return PurchaseProcessingResult.Complete;
        }

        public void OnInitializeFailed(InitializationFailureReason error)
        {
            OnInitializeFailed(error, null);
        }

        public void OnInitializeFailed(InitializationFailureReason error, string message)
        {
            var errorMessage = $"Purchasing failed to initialize. Reason: {error}.";

            if (message != null)
            {
                errorMessage += $" More details: {message}";
            }

            Debug.Log(errorMessage);
        }

        public void OnPurchaseFailed(Product product, PurchaseFailureReason failureReason)
        {
            Debug.Log($"Purchase failed - Product: '{product.definition.id}', PurchaseFailureReason: {failureReason}");
        }

        public void OnPurchaseFailed(Product product, PurchaseFailureDescription failureDescription)
        {
            Debug.Log($"Purchase failed - Product: '{product.definition.id}'," +
                $" Purchase failure reason: {failureDescription.reason}," +
                $" Purchase failure details: {failureDescription.message}");
        }