NUDEBT incompetence

If I could give them 0 stars I would.I recently received email upon email from these guys regarding an amount of R350 that they say is owed by me to Telkom this after my brother was contacted telephonically to demand payment from him for this non outstanding amount of R350,why they contacted him only they would know.I recently changed banks so I contacted Telkom to change my debit order details .Unfortunately Telkom tried to debit my old banking account again so I paid via their portal.Telkom confirmed that the payment was received and nothing is owing, this proof has been attached to my emails to nudebt. Now nudebt is constantly harrasing me for the R350 they say is still owing , I have received letters threatening legal action on behalf of their client Telkom ,threat of a notice of default judgement for a 20 day "overdue" account that has been paid etc.I have contacted them telephonically speaking to a guy named Vusi who couldnt seem to get my ref number correct over and over and to a lady whose name I cant remember who told me my payment to telkom does not show on their system yet.I have sent emails to their *** email address as well as to *** , Bill for R350 due 27th March in Notice of final demand . Notice of default judgement for an amount outstanding for 20 days strangely they do not state what the amount is.And then another Final demand where they have my ref number as the amount outstanding that needs to be paid by 31 March. That would make the amount outstanding more than 502 million dollars. Now what type of company is nudebt ? and is Telkom honestly trusting this company to do collections for them .Contacting Telkom has also not helped.Fortunately Telkom will be debiting the correct bank account for my bill next month as has been confirmed twice.If nudebt management happen to read this matbe they would try and rethink their staffing contingent or management capabilities.