Can't leave beta version on Android

Hi. I joined to the beta version of Android, but I wanted to leave, so I went to the Google PlayStore and I "left". I waited a few minutes when it said that I can join again, but an error appeared saying that I still being part of beta testers, and I may want to reinstall the game. I didn't at the moment, because I wanted to be sure, so I opened the game and in fact it still was on beta. I reinstalled it many times but didn't work. Not only happening in my current phone, but others I have with the same Google account. I need help, please. Thank you.