Struggling to cancel mobile contract

I m struggling to cancel my mobile contract, I cannot call Telkom as I m told to use WhatsApp chat by automated voice response. Whatsapp chat does not help at all.

Tried online self-service cancelling but immediately get a response saying the ''request has been closed and resolved'' without calling me.

Debit orders are now 4 months over the contract expiry date.

Please help to cancel my contract.