Harassment, failure to obtain info from Telkom who is not updating payments

NuDebt is harassing me continuously due to Telkom accepting my debit order on the 15th. The more I advise them I am not in arrears the more they insist on proof of payment every month. I pay on Telkom app, why must I provide evidence when I am up to date by Telkom. Telkom advise I must ignore them but they phone me every second day, they do not listen to me and keep insisting on proof of payment indicating Telkom is slow to respond to them. Why is this my problem. STOP HARRASSING ME!!! Remove my nr *** or I will take legal action for harassment!