Ridiculously high bill

I have had a data contract with telkom for almost 3 years now.

Had the 80GB LTE then i upgraded to offpeak uncapped last year in October at R449.00 per month.

The Past 3 Months my bill has been ridiculously high, last month i paid R802 and this month i have received an invoice of R737.00 i tried to call the customer care line and i wait for hours on the like.

at this stage i am even considering to cancel the Contract because i can't Continue to pay this high amount