Momentum is useless yet they know when you submit a tax return

After having cancelled my medical aid with Momentum some two maybe three years ago, I am still to this day handed over to collection attorneys for a payment which I was not aware nor informed of. I asked literally more than 20 times for a copy of the document, which has not been provided, yet every time I either do something with my pension or submit a tax return, Momentum is on my case.

Either provide a copy of the document or leave me alone.

I have so many emails detailing my requests.