Cell C trying to steel from me.

Cell C sucks. Had a R99, 5GB a month contract for about a year, and suddenly i get billed R1200+. I phoned and they informed me that it is for the OTHER two contracts that i took, which i didn't. I cancelled it, and have been billed between R1200 and R2500 for the last 8 months. Have to phone the bank every month to reverse the transactions, and i've phoned CellC after each debit order, but still get billed the next month.