Account query - NO customer service

Following my previous complain about poor service from MTN on 16/2, and their reply on 19/2 (MTN *** from Alice vd Merwe), i have now received my account billing, and went back to the MTN shop in Vaal Mall. After an hour waiting in line, i finally spoke to Stefan, and explained my problem. he initially said they will log my call with MTN, but after speaking to someone behind closed doors (assuming it was the manager), i was advised to phone MTN myself, the shop cannot assist. needless to say my original complain has not been solved, and after seeing my tax invoice, i even have some more queries! i phoned 808 and spoke to Siyabonga for 45 minutes, but he is also unable to assist.....he cannot find any useful information on my bill. All of a sudden there is also international calls on my account, which makes me believe that someone has ******** access to my account/number?! Can someone at Mtn PLEASE assist me to sort out this mess? i suggested that my sim/number be changed to prevent further problems whilst i try to sort out my account, and again was referred to MTn, the store at Vaal Mall cannot assit me?