Handed over for collection two year after cancelation and no contact

I had a Fibre contract with Supersonic from end 2020 till the end of 2021. I sent my cancelation notifications at the start of Dec 2021 to be effective at the end of Dec 2021 as I was moving and handed the router back to them. Then I received a invoice at the end of Jan for Jan 2022, I called their call centre and had it sorted out, or so I though. Now TWO YEARS later I go an email from a collection agency staying that I have been handed over for none payment by Supersonic. During these two year I have not received a single statement, invoice, message, email or phone call from Supersonic to inform me that there is still any oustanding amount due to them.