contract says R199 per month but they pay R269-R350

i HATE you Cell C, you are big ***** . your contract phones are R199 per month but i end up pay R269-R350 WHY? I have been given a extra sim card with my second contract and when i found out that i pay extra for it i cancelled it 3months ago but im still paying for it. i have been calling the call center for like four months now regarding these extra fees that i pay every month, and every month i get a different story for the extra funds. you have the RUDEST staff on earth who cant communicate with clients. you will never a single cent from me until you do the right. SIES MAARN