Harassment By Nu Debt Management MTN

They are constantly harassing me with texts every week, stating that I owe MTN. I called MTN and they confirmed that my contract ended in 2023 and I confirmed that I don't want it renewed and I owe them nothing.

I have explained this multiple times to Nu Debt but they keep on harassing me. Worse part is that I don't even use MTN anymore, I am with Rain and Cell C so what nonsense are they on about.