Signed for TopUp Contract

I upgraded my contract on 06/02/2015 for My MTN choice topup 1GB R269pm Samsung T535. <br> Selesperson Bongy Mainu - SAC0356 MTN Plaza 21b -Hatfield. Manager Thabang<br> The contract was signed at MTN Hatfield shop with the following conditions:-<br> 1. 24 MTH My MTNChoice 1GB, 2. R269 per month, 3.TopUp Contract .<br> After 3 months I received statement stating that my account will be debit with R 3359.57.<br> On the 30th of April I called MTN shop regarding my account, the salesperson Bongy, said that my contract was open line not topup contract.<br> From that point I ask Bongy why the line was open contract, she said that the system was offline when I took my upgrade and no follow up was done to make sure that line is topup contract.<br> <br> From my side the contract state clearly that the upgrade was topup contract and that is what I signed for.<br> I have opened more that 5 requests from mtn call centre. I received reply from MTN call centre,<br> saying that I must visit the store where I opened the contract for further assistance.<br> I have called MTN shop more than 20 times from 30th of April until today(09/09/2015) with no help.<br> Can someone assist me, what to do.<br>