Harassment by Nudebt and Telkom

I do not understand why Telkom is saying I failed to make payments on my account. I never instructed Telkom to stop debiting my account ( which always has funds btw) or even terminate any of my contracts. I am constantly being harassed through numerous calls and messages with threats of legal action by NuDebt.

Can someone please explain what this is in relation to? What am I paying for? And which of my Telkom contracts is this in relation to?