Worst Service Ever!!!

I took out a contract with MTN around December 2013. Everything was fine until i switched banks (Absa to FNB). After noticing that my account hasnt been debiting i emailed mtn custmore service to update my banking details as ive changed banks. After goin back an forth on email sending them my details and arranging debit dates they have failed to assist me and have now handed me over to a debt collecting company. Once i received a call from the debt collecting company i called mtn accounts to find out as to why this has occured adn they explained to me that they still cant debit the money just to find out that they havent changed my banking details. I have all the email proof) i went and deposited R2200 as my account was in arears because the debit order still hasnt been setup as they had my old banking details. i have all the proof on email. Cellphone number thats on contract: ***