private async Task AcklowledgePurchaseAsync(string token) { AcknowledgePurchaseParams acknowledgePurchaseParams = AcknowledgePurchaseParams.NewBuilder() .SetPurchaseToken(token) .Build(); // Consume the Non-Consumable Product BillingResult result = await _billingClient.AcknowledgePurchaseAsync(acknowledgePurchaseParams); if (result == null) { // Failed to get result back. throw new InAppPurchaseException(PurchaseError.Unknown, "BillingResult is null"); } if (result.ResponseCode != BillingResponseCode.Ok) { throw new InAppPurchaseException( result.ResponseCode.ToPurchaseError(), result.DebugMessage); } // Otherwise, the Acknowledgement succeeded. }