Still debiting my account after 5 months

I ported to a different cellphone provider effective 1 October 2015. Altech Autopage has continued to Debit my account every month as well as the new provider. I contacted the Autopage call centre 3 times on 3 March without any answer, holding on for between 35 and 45 minutes. On 4 March I spoke to 4 different consultants who cut me off every time therefore I still don't have any answers. Altech owes me a total of R3161.51 to date.