IPhone 4 calls not working after coming out of an area with no reception

Question

I bought my boyfriend an iPhone and for some reason, everytime he has to use the subway and come out to make a call (with full reception), the call itself will not go through. It also "locks" the phone app so that when he exits it completely and deletes it from the background programs and re-opens it, he still can't make calls. It use to be that he turn off the phone, and turn it back on, and that reset the problem, now that doesn't work. We tried resetting his phone, factory restoring it, factory restoring it to new phone, and nothing so far has worked because as soon as his reception cuts out and he regains reception, the phone has the same problem. Even text messaging won't work, it seems to cut the entire reception.
Unfortunately it's past the 1 year now and the warranty with Apple has expired. I bought this phone as a gift and an outright purchase so, as most of you know, that was expensive! I am extremely upset now that a simple function a phone is suppose to have is working so poorly. I have read that others have been experiencing issues with making phone calls, whether it's outgoing calls being muted, etc. and all Apple tells them is to bring their phone in to an Apple Genius and get a new phone. There seems to be even more issues with making calls every time a new update for the software is release. I work in the cellular business and have tried every form of troubleshooting I know.
If this is a software issue, why has it been going on for so long, and why hasn't apple fixed it in the software patches? Has anyone found a fix for this yet? I really need his phone up and running, we're both phone dependent, both with iPhone 4, and both extremely unhappy.

Answer 1

I don't know the laws in Qatar, but in most countries there's nothing illegal about it, and nothing Apple can do about it unless Carrefour is claiming to be an authorized Apple dealer.
It's difficult to identify the country in which an iPhone was originally sold. A list that purports to list model numbers and countries of release can be found here, but there are no guarantees that the list is accurate. Again, please note that probably will not be able to send the iPhone directly to the service center in another country; most if not all will not accept an out-of-country shipment and will not ship a replacement out of that country.
Otherwise, you'll have to try to negotiate with Carrefour.
Regards.