Nudebt is the worst, service providers should stop using them

Worst service i have ever dealt with, harass a person, don't respond, but quick to phone when they not receiving payment. Telkom sent me to them for missing a payment because it didnt reflect on their system quick enough. this was two months ago. To date i have been called, emailed, watsapped, smsed by Nudebt harassing me for money. i have sent them more than 4 emails with proof from telkom that there is no outstanding fees, yet they do not respond to me but still send mail,sms, message and call constantly. i last spoke to a Nosipho that promised me feedback and still nothing. i am very lost as i do not know what to do anymore. this is going to affect my whole credit because of their incompetence.