Matrix *****ulently upgrades client contracts

Worst company ever, Matrix continue to debit our account after their agent *****ulently upgraded our contract which led to double billing of vehicles because the vehicles now have two units. An agent of Matrix called me early this year and told me that Matrix wants to replacement units on our vehicles because units are old and Matrix cannot guarantee that they are still working fine. She then proceeded to arrange for new units to be fitted. I have never signed any paperwork for this or agreed to an upgrade, I was told that Matrix is replacing old units with new tracking units for free and I will continue under the same month to month contract arrangement. After the double billing started I have been following up with them since February (multiple emails and phone calls to no avail), they have not credited my account for double billing and they have not reversed the *****ulent upgrade even though they know that it is *****ulent. They are billing me on a vehicle that was on a month to month contract even after it was terminated as it was written off because of this *****ulent upgrade..