Upgrading of account throuhg lies

Vodacom marketers duped me to accept a better package(More data,less payment)After accepting ,my package was upgraded to pay additional R1800. I called end October, requesting to revert back to my original package.The cancellation/retention consultants promised to correct the matter. However, it is end November,and the bill is still R3100. What makes it worse is I only receive an invoice for R1400(home wifi and a modem)The other two numbers,pushing the account to R3100, is just an SMS. I requested a detailed, but to no avail.

Please assist Sabata ***