Unable to cancel phone line

I requested cancellation of my land line on 9 April 2018 by email, with all required supporting documentation attached. I received confirmation of receipt of this request. My ISP released my ADSL line back to the Telkom holding pool on 4 June 2018, and they provided me with proof and the reference number. I received an invoice from Telkom for June and and they debited my bank account on 1 July. I have contacted the call center many times to resolve this, but someone from retentions phoned me and said that the ADSL line has not been released to the holding pool so the cancellation could not proceed, which is not true. Many people seem to be experiencing the exact same thing. This keeps getting "escalated" but nothing is being done. Can somebody from Telkom please cancel my account and refund my money. Or at least let me know what is happening.