Cell back 6 times!

My husbands phone was 7 months old when it went in for the first time. it has now just been sent away for the 6th time and he is due to upgrade in 2 months time! Every single time Vodacom has it for about 2-3 months and tells me they cant find a problem! Twice they have sent a reconditioned phone which has the same problem! They don't seem to want to make any further effort to assist! They haven't bothered to contact Blackberry to try and sort it out and seem to think I am lying and have nothing else to do with my time than keeping taking a cell phone in for the same problem! I was going to just leave it and not bother to take it back in! And if I put it on Hello Peter they quickly just \sweep it under the rug"but don't actually help! I am totally appalled with their lack of customer service and trying to help their customer!"""