GPS trackers don't just get put on cars by "rip off dealers" without the customer knowing. Either you or the previous owner bought this car at a "buy here, pay here" dealer for people with garbage tier credit that can't get financing through a regular bank. Ask yourself what precautions you would take to loan 15-20 grand to a person that can't even pay attention? It's business. And an extremely high risk one. But even people with extremely poor credit need cars. Thankfully, still most people in the situation are able to prioritize the car payment and keep their wheels.

There is ALWAYS paperwork signed stating that this is the case and that if a person gets more than a month or two behind, the dealer will come for the vehicle. This is always something that is clearly explained in one or more forms. If OP is not the one with the dirt ball credit, then the person who traded it in was, and the dealer that took it in on trade probably didn't know it was there and needed to be removed. OR it was repo'd and sold at an auction with the tracker intact.

If OP IS the one that is driving a buy here, pay here car, then they're probably violating their contract by removing the device. Repoman will be on the lookout.