Pathetic Service Recieved from Vodacom

Good day to whom it may concern,

In November 2020 vodacom had a promotion for free fiber installation and first month of internet usage will be free,during the time i had some internet issues with another service provider and i was more than happy to switch to vodacom.

End Novemebr 2020 I was not billed internet was working fantastic, till end of December 2020 where they then DOUBLE debited me for the month of Nov and Dec 2020, I called 02 Jan 2021 to to resolve this matter and they advised that it has been captured incorrectly and they will send it onto their billings department who will contact me,today 18 Jan 2021 I have not recievd any feedback agents refuses to transfer me to management and my matter is still not resolved as a customer I'm extremely dissapointed in their customer service as they keep telling me some one will call me but noone does,please help as I do not know what go do and will be billed again at the end of Jan 201