Hathway — Hathway connection - unnecessary billing

Hi i was user of hathway for broadband for about 1.5 years but during lockdown due to there services i stopped using it. There was some dues on the hathway account which is paid on 14th June and the router, wifi device was also picked up by hathway people but still i am getting payment/renewal messages for hathway.

I have send them multiple remnders to stop sending these but still getting messages and email.

Please help in resolving this issue as i have tried my best but nothing work