My iPhone 3GS has been fine up to this point except a couple months ago the mic became defective. I took it to the genius bar and they swapped it out for me (under warranty till October). However the replacement unit they gave me had signal problems; so I got it replaced again. Now on my 3rd 3gs and this one has a dead pixel. I am very dissapointed At apple for giving me apparently faulty iPhone replacements, will it be possible for me to get a full refund?