Extremely poor customer service

I just received my account statement for the end of January and my account is R100 more than I usually pay. After getting off the phone with Vodacom I was notified that the R100 is a handling fee because THEY debited my account twice last month and the second debit bounced. How can I be charged for their glitch!! I had enough money in my account for the original debit.. It is not my fault that my account was debited twice. To make matters worse Vodacom have still not refunded my bank account for the fees associated with their second debit as promised. It is now 16 days later. This level of service is pathetic. And I will not be renewing my cellphone contract and changing to a different service provider. Shocking service!! After being with Vodacom for 13 years! I will not be paying an additional R100 as a handling fee for their glitch!! And I'm still waiting for my bank fees associated with the second debit to be refunded to my account! I still haven't been contacted by Vodacom.