double charged! no help!

Vodacom has terrible service when you need to get in touch with them!!! My debit order didn't go through last month so they deducted that amount along with most latest invoice in one debit order, which is fine. However I had already made arrangements for a another debit order to go off. Therefore I was billed for the same invoice twice! I've been trying to get in touch with Vodacom to sort it out, but no luc**** I asked for a call back, but nothing!!! I try to phone them, but nothing!!! this is not the first time I tried to query something and ask for a call back with no success!!! Terrible!!!