Cell C
Unable to sort out returned data stick after 3 mon

I purchased a data modem from Cell C PMB on 16th Oct 2012 returned it within 24 hours as no coverage in my area. I have been trying to have the debit removed from my account since then. Their call centre is useless all the do is say they will attend to it. Send me SMS to say they ars attending to it but cut my service off on 1st Jan not withstanding that I have that I have paid for my cell phone contract. I am told they will E mail their superiors to resolve the problem but nothing happens. They do not reply to e mails or fax