UNAUTHORIZED DEBIT

I have been customer of Altech for more than 10 years but due to ongoing bad service I decided to end my contract with them at the end of October 2014. On 30 January 2015 an amount of R397.45 was deducted from my bank account. I contacted the call centre on Saturday 31 January and was told that this deduction was a mistake on their side and that I should be refunded within 24 hours. I called again yesterday, Tuesday 3 Feb. I had to hold on the line for 45 minutes before I was able to talk to a consultant. The consultant could not give me any answers and subsequently put the phone down. I then sent an email requesting feedback regarding my refund and STILL no answer from Altech. Who gives Altech the right to deduct funds from a past customer's account?? They just do as they please and think that they are above the law! It takes on average more than 30 minutes to get through to their call centre, which costs more money. I want my money back and I will not stop until the funds are in my bank account.