Cancelled Contract

I called Cell C last month to cancel my contract and settled my outstanding balance in full on the 27th February. My debit order still went off on the 1st of March for February which I'm perfectly fine with. At the beginning of this month i ported my number over to another service provider, only to find that Cell C now feels that they should send me a bill for March which is due at the end of this month.<br> <br> I called through to customer care, retention's and accounts , spending over an hour on the line, and no one could help me, some saying they cant find my number on the system and others saying they will call me back (like that is ever going to happen).<br> <br> In the event that i call the bank to cancel the debit order, I run the risk of having my name black listed, so I really don't have a clue what to do.....But I'm not willing to pay R500 for nothing<br> <br>