incompetence

My contract expired with mtn in October 2014,i was advised the d/o would automatically stop, to my shock early feb 2015 i discover my account is still being debited, i decide to take up an upgrade since well i was being debited for a contract which had to be terminated, funny enough after the upgrade, genius departments of mtn do not debit the account the next month, they suspend the line , Then send me letters that my account is i arrears and legal action will be taken if payment is not made.<br> I do not know who should be held accountable for such incompetence, I'm am not pleased with their service just want to terminate the damn contract, cant even go through to their 808 line every time i call them and their branches cant even assist me, talk about customer care.pathetic.