Unity IAP causes Google Play security alert

Hi. I'm using Unity 5.6.5f1 with Unity IAP. When I wanted to build my game, got conflict error between GoogleAIDL.aar and GooglePlay.aar. So as someone suggested to remove GoogleAIDL.aar, I did it and that fixed the build. But now Google Play sent me an alert with this text:

 Your app is using an incorrect implementation of in-app billing. Please see this Google Help Center article for more information.
 
 Vulnerable classes:
 
 com.google.android.gms.internal.ct
 com.google.android.gms.internal.cv

 This information is intended for developers of apps that have a vulnerable implementation of In-app billing. 
 
 If your app is invoking the In-app billing service without setting a target package for the intent. This can enable a malicious package to bypass the Play store billing system and access items that have not been purchased.
 
 Steps to fix:
 
 If you are using IabHelper, please start using the latest SDK. 
 If you are manually invoking the In-app billing service, please ensure that you are calling Intent.setPackage(“com.android.vending”) on any intents to "com.android.vending.billing.InAppBillingService.BIND".
 Sign in to your Developer Console and submit the updated version of your app. 
 Check back after five hours - we’ll show a warning message if the app hasn’t been updated correctly.