There is no item in the catalog with an ID matching the product ID in the receipt

public PurchaseProcessingResult ProcessPurchase(PurchaseEventArgs e)
    {

        if (!IsInitialized)
        {
            return PurchaseProcessingResult.Complete;
        }

        // Test edge case where product is unknown
        if (e.purchasedProduct == null)
        {
            return PurchaseProcessingResult.Complete;
        }

        // Test edge case where purchase has no receipt
        if (string.IsNullOrEmpty(e.purchasedProduct.receipt))
        {
            return PurchaseProcessingResult.Complete;
        }

        var wrapper = (Dictionary<string, object>)MiniJson.JsonDecode(e.purchasedProduct.receipt);
        PlayFabClientAPI.ValidateIOSReceipt(new ValidateIOSReceiptRequest()
        {
            CurrencyCode = e.purchasedProduct.metadata.isoCurrencyCode,
            PurchasePrice = (int)e.purchasedProduct.metadata.localizedPrice * 100,
            ReceiptData = wrapper["Payload"].ToString()
        }, result => CompletePurchase(e.purchasedProduct),
                                            error => FailedPurchase(error)
        );

        return PurchaseProcessingResult.Complete;
    }

void FailedPurchase(PlayFabError failNote){
        Debug.Log("Validation failed: " + failNote.GenerateErrorReport());
    }

    void CompletePurchase(Product product){
        if(product.definition.id=="rf.pack.gold100"){
            AddGold(100);
        }else if(product.definition.id == "rf.pack.gold500"){
            AddGold(500);
        }
        else if (product.definition.id == "rf.pack.gold1000")
        {
            AddGold(1000);
        }
        else if (product.definition.id == "rf.pack.gold3000")
        {
            AddGold(3000);
        }
        else if (product.definition.id == "rf.pack.gold10000")
        {
            AddGold(10000);
        }
    }


    void BuyProductID(string productId)
    {
        if (!IsInitialized) throw new Exception("IAP Service is not initialized!");

        // Pass in the product id to initiate purchase
        m_StoreController.InitiatePurchase(productId);
    }

    public void act_Buy(int index){
        BuyProductID(Catalog[index].ItemId);
    }

My I ask is "0" your Primary Catalog?