Improperly scanned phone now before other phone deactivated

I don't understand how all the sudden my phone I had that worked just fine was all sudden deactivated one night just a few mins after I was it and the new phone I got for Craigslist For $175 dollars they say is improperly scanned and they won't do anything to help a person out when they should be doing everything they can to keep their customers happy instead of just blowing them off and ripping them off I've spent over$ 300dollars in two months now on phones that I can't even use how in fair is that