Poor service from cartrack

Yooh what a poor service I received, I bought a car which came with unit from previous owner, I was willing to take over the unit nd continue with the contract of the previous owner however it was an hustle to be assisted even to app logins was a hustle after getting my logins I couldn't locate my car meaning the previous owner still hv access to their app nd he/she can still locate the that doesn't belong to him/her which put me in danger. they asked me to email them a proof that im a new owner which I did however I was not assisted. They asked me to email them copy of my ID nd I did however nothing was done. They keep saying ot will be resolved. I want them to de-active their unit on my car so that the previous owner cannot locate a car that doesn't belong to him/her nd I Want them to remove my banking details from their system because I don't hv any contract or agreement nd they even sent Debi check mandate which can't be declined.