A R99 Contract Plan ends up as R814.15 Bill

I have never been so ********** before, I took out a contract with MTN 06.06.2015 at the Shopping center L58 Brackenfell store. I then made it clear to the sales person Jasmine Brett that do not want any extras as this simcard will be placed in the ipad for 6 year old son. i basically just need the phone and she assured me that the bill will only be R99 every month as it is limited to. We then signed the contract and off we went, 6 Months later i get debited with R814.15 instead of R99.00 as stipulated on the contract because we on a MTNCHOICE R25 @ 99 Plan.<br> <br> Without notification the money gets debited from our account.<br> <br> mtn gives me a contact number *** which stays engaged or posibly dont exist because iv been trying that number all day for two days. I cannot affort R814.15 for a R99 contract which was agreed on and to top it off. That contract number is in a ipad that cannot make calls so im not sure where a bill of R814.15 could come from. not to mention we dont use the ipad my son plays games on there. The money is debited and needs to be credited. i have been a loyal customer by paying my contract bills on time. Please escalate this to Mtn Brackenfell.