Tracker expired account

I have settled my account with this sertivce provider and entered into month to monht basis. After enquiring about the status or functonality of the tracker installed without reposponse i terminated the contract. I ws handed over to atorneys and obliged to pay the outstanding fees. Tracker is now sending me mails about invoice of which the account was not resinatted after being settled. They are using tack tick to milk my accont while they have not come back and agrred if we continue service or not. I sent them mail and they dont even bother to respond.