Odd network problem

[anon(9186693)]

My phone was originally purchased SIM free and has been used on several networks, e.g. Talktalk (vodafone), Giffgaff (02 I think) in UK and Red Pocket (AT&T?) in USA. When I inherited it from my son, I rooted it and installed Carbon ROM. Recently I tried to sell it and found that it won't make calls or send texts on any network but Talktalk. It seems to recognise other SIMs and gives a 'Registered on Network' message but on trying to call a number I get a 'call ended' message and cut off within 0.5s. I tried re installing a stock ROM but I've got the same problem. Any advice gratefully received.