Seriously bad customer service - incorrect exorbitent debit for the last two months

I have been using Telkom data and wifi router for about 4 years and I am on a R199 pm contract. In May 2020 I was charged R698.56 and again in June. I reversed the incorrect charges twice and now they have debited my account with R1,397.12 after I reversed the second debit. This means I am paying more that 3 x my contract monthly charge. I tried to call but their numbers ***, ***, 081180) seem to be out of operation as the call just get ended without going through. I emailed my query to 10213 <***> and '***' but I am not receiving any response..not even an acknowledgement of receipt.