Checkers sixty 60 app

I wish to do online shopping and chose checkers siwty60 because it's cheaper that other stores. So I download the app and fill in the usual details they require and choose what I want. Fine. Then it asks for my bank details of which I do so. This is the second time the app has told me my bank card has expired. Huh? It expires in two years time. Something is definitely wrong there. I'm gonna give my card to a friend who will do my shopping for me. Other online shopping apps work better, are easier but charge more. I guess in this country some apps are ******* and others charge more but get it right. Ouch!