Cell C
Cheating me out of my airtime

I lost my contract sim last month and recently replaced it at a cost of R50.00. I put the card into my phone today and it prompting me to recharge as ive used over R600.00 already. I do not get this guys. My sim has been with me the entire time. Please advise for what these charges are. The contact number supplied is not my contract number. Please call me for this info.