[AC Question]

I've had a Samsung Note 4 since new and I wanted to replace it with another Note but not the latest model because of the cost. So I ordered a "NEW" Note 4 (AT&T unlocked) phone from a seller on eBay. I now use Consumer Cellular as provider. When I switched from T Mobile all I did was put in the new SIM card and off I went no issues. WHen my new (from eBay) phone arrived it would not recognize the SIM card. No matter how many times I tried it would not recognize the SIM card. The seller took back the phone and sent a new one. Well the new one has a serious problem, when I make a call the other party can not hear me. If someone calls me it works perfectly. I contacted Samsung tech support and they could not solve the problem and said that I would have to ship them the phone for service and that I would have to pay for the service as the phone was no longer under warranty.
I have sent a message to the seller asking for a refund.
Now I am back to square one. I want a new phone, with a warranty, a large screen, and if possible not tied in to a carrier and all their built in apps.
Can you offer some suggestions.
Thank You