Cell c poor service

I went to Cell C store ****arney Mall to cancel my contract early march 2018.

i was told to call 084143 on the 1st of April to serve a notice. i did call and i was advised that my contract will be cancelled. but now i was billed R175 yet my contract was R99. tried to call cell c for clarity but i did not get help as cell c urgent had an attitude towards me.

here is the ref number i received from cancellation ********** 12995.

i need cell c to refund me the extra money they debited and cancel my contract with immediate effect.