Billing Problem

I took out a mobile wifi contract with Telkom in October 2018, Telkom captured incorrect information specifically the banking details, whenever they tried to debit, they did not find an money due to account being non existent at FNB.

I got disconnected and went to Sandon city in store. they updated my details and I was asked to pay a certain amount to get connection and so I paid. December 2018 I was not debited again and I'm told everytime they try to debit and they don't find money in "my account" Telkom charges me R200 in addition to my monthly instalment.

I need this fixed as its not my fault that Telkom captured incorrect details.