Complaint about webafrica and vumatel

My account has been debited twice in one month in December and I was told that it is under investigation, however no feedback or reference was giving for said investigation and no money was refunded. Now this month it has happened again. The WhatsApp and agents are of no help. This is bad and pathetic customer care as one agent even got upset with me when I tried to explain that the money was indeed off my account. I was then sent a screenshot of their account that stated that their was no second debit but my bank statement proved that they had in fact debited me twice. And still no response and no actual care about their customers. To debit someone twice and in today's economy when every cent counts and you still don't provide feedback to your customers. Really bad service, who do I contact to get my money back ?