Billing not what I agreed upon

I have requested a relocation, it took place a month ago. I found that vodacom had to move me over to openserve as they were the service provider here.

Today is the 12th and they debit my account for double the amount agreed upon. Even after I have emailed Sibusiso Makhubu regarding the invoice I received and requesting when the debit order would go off.

To which I have received no response and being billed by an amount double from what I agreed on.