Complaint -horrible service after cancellation

Telkom is the worst provider ever . I cancelled my WiFi contract in 2023 October and they confirmed cancellation . The next thing Nudebt is calling saying I owe Telkom money . I called Telkom to confirm with Nudebt that I don’t owe them anything and after months they finally confirmed it . Now I want my refund since I overpaid and every time I call I am asked to email my bank statement and ID copy edict I have done but no refund . When I call to follow up on the refund the call centre agents put me on hold for long periods and never come back . All I want is my refund .