Vodacom - Customer Service (NO SERVICE)

I have an account with Vodacom - I used to pay using the App which was updated and became difficult to use as a pay portal. I contacted Vodacom to ask them to initiate a debit order on my account for the 25th of the month. November all went fine - then December the 13th ( 2 weeks later)they took the next payment. Then on the 17th January they tried to take the next payment( which was returned as i had not been paid yet) this as instructed was not my debt order date. On the 25th January they did not try and debt my account, i had to go and pay it at Checkers. They have now charged me R100 for a non payment. I phoned and complained no one has phoned me back even after saying that they will esculate this and phone me back - absolutely nothing. Vodacom is very quick to take your money but not admit they have made a mistake. I will be cancelling my cell phone contract in June when it is up for renewal.