Disgusting service MTN

I am so irate......... Does anyone know what the heck is going on in MTN...... I get 1 story from the store agent and another story on the 135 accounts..... I need to do an upgrade and Noone can assist me. I get left hanging on the phone while the agent probably went to lunch or something.

In November MTN refunded me an amount of R240. A few.days.later I get an Sms saying my line will be disconnected because there is R240 outstanding on my account. I then go to the mtn store and pay the R240 back. Now I want to upgrade and this R240 is a problem. The girl in store talks about a R480 which I have no idea why and the agent on 135 says my account is up to date.