TRACKER FROM HELL, RUN

My contract was ending January 2022. I have tried a couple of times to get hold of them, through emails and calls. They don’t answer. I wanted to cancel my services with the since last year, but it is hard. I keep on getting billed and being called by depth collectors that I’m owing them. How is it that I have sent an email mid Feb informing them that I’m not continuing with them but still get billed. I’m so tired I don’t know what I need to do to get out of this mess.