Cartrack are a ********, would not recommend!!!

In July 2020, I cancelled my relationship with Cartrack, because of poor service, having used them since December 2013. My contract was three years long, so essentially have been on month-to-month payments since roughly December 2016. In the past week I've received three calls about outstanding cancellation fees -which outstanding fees when I was on a month-by-month and one of their consultants had said I wouldn't have to pay anything because my previous contract had matured in 2016 already? Be careful, these people will try to **** you if you do not understand your rights. I'm waiting for another call from them requesting this or for them to debit my account, so that I can proceed to my lawyers.