Netstar harassing me

I took a contract with Netstar for 3 years. My car was written off 3 months after I took this contract. I reported to Netstar and I was told that I cannot cancel until 3 years lapses. The contract expired in June 2024. I emailed them in July 2024 asking them to cancel the contract. They didn't bother. It was back and forth until eventually in August, I received confirmation via email that it is canceled. Surprisingly I still get calls and emails from them threatening with legal actions for non payments. Netstar is harassing me, they need to stop.