Urgent help needed for this bad service of Telkom

We got big problems with Telkom.As we cancelled our fibre line in November2018 as woodlands Telkom frontdesk shop assistant advice us to cancel it online. We already moved out of the estate 30 November 2018.And never received any reference number from Telkom as from today.the line is still open and we get billed now for 3 months and the fibre line was month to month.I went in to Telkom frontdesk again on 8 January 2019.The line is still open and they can't assist me with out any reference number.And refuse to help me solve the problem.Where to now from here.They not very helpfull in this matter and rather been busy on there own phones.Think the new tenant score big time still using our line that Telkom never closed and still keep on billing us.