BAD SERVICE AND CHEATING!!!

We handed in our Sony Xperia phone a FEW MONTHS ago at one of the branches for repairs. I checked in on a weekly basis but no one could give answers, due to a strike!? We tried calling the MTN call centre, the number is either not working or when it does people simply hang up. <br> Today however, got through to HVRC department and got informed that our phones warranty has been voided because the USB port has physically damaged!??? HOW does a USB port get physically damaged when (original charger supp****) only the original Sony material has been used? We are the most sensitive people that i know when it comes to electronics (i.e phones, consoles, remotes etc) and theres no way that handset had 'physical damage' - I am saying it as it is, and MTN deliberately broke my phones port to void the warranty, to not stand for the repair cost due to the fact that our contract expired a week or two after handing it in!! Thank you MTN for a horrible experience.