Bad service

I app**** for a Fibre line through Telkom of R399. I Provided my bank details for a debit order to go off each month on a 24month contract.My installation was done on 28/08/2021. I received a statement on September for a charge from 09 August , when I haven't used the service. I called the call center on numerous occasions to fix my billing. To my surprise my statement for Nov shows an amount due of R716,21 . Each month the billing differs and the amount due is never amounts to R399 as per the agreed contract.I'm not getting any assistance. I asked for a team leader to call me back. Until now I didn't get the call and my billing is still not fixed. I'm at the stage of cancelling the contract