Ridiculous billing due to instructions not followe

Good day. <br> <br> I added a new line on my existing contract A***. I had spoken to a sales rep and clearly advised that i want a TOP up contract and not a contract that will have a bill. The line should stop immediately once the airtime is finished. This call was made with Kgabo on *** .<br> I received an sms that my credit limit had been increased to 2643.00, of which as per previous problems with MTN over reaching my credit limit on Top up ***, i thought this was to accommodate the new line.<br> I then received an sms that my line is locked and i have reached my limit , and i called and requested that the call recording is sent to me and to immediately set my limit to 0.00 on ***.<br> i am still waiting and the dispute has not been followed through.<br> Today , an invoice was sent to ***, that the bill is R2900.00.<br> I WANT AN EXPLANATION .<br> I REQUESTED A CONTRACT AND NOW I AM BEING TOLD IT IS A MYCHOICE CONTRACT, BUT I REQUESTED THAT ONCE AIRTIME IS FINISHED, THE LINE SHOULD BE CUT. I WANT THE R2900.00 CREDITTED IMMEDIATELY.