Bad service

Good day.

I took out a rain contract last year June and it started acting up in regards to connectivity. I tried to contact them via email and call and no response. I then tried to cancel via their portal and stil no answer. I then unplugged their router and put it back in the box. This year they came back and told me I owe and that if I want the debt to be squashed I should return their router via me delivering it or setting up an appointment to fetch it from me. I did that and there after ofcourse they ghosted me. I then received an email saying they are trying to get a hold of me and they attached a number that was wrong and I rep**** back to them saying I don't know the number and I gave them my contact number. They went quiet again. A company started harassing me saying they are collecting rains debt and that I would be listed if it was not paid. I am utterly disappointed in rain as you can never get through to them but when they come back with huge debts all of a sudden they can talk. The last email they sent was that I owe 2 months of usage. And I asked for the invoices but nothing has been sent. Please help as the collection company continues to harass me.