MTN contact centre

Again my call can't be found whereas their calls are recorded.HOW POSSIBLE!!!Customer service or customer care very unprofessional. Queries are not attended to .on the 4th March I called in to cancel the contract but to my surprise I was put on month to month contract and now am billed and they are threatening to suspend my phone.My 24 months contract with them ended on the 31st March 2026,I called them on the 4th March 2026 yo cancel.WHY WAS the cancelation actioned.