I certianly wouldnt allow them to drive the car around with it still under my credit.....what happens when they do just decide to stop paying, you're credit suffers. I would have the grandmother, being that she is the one harrassing you, find a resolution to the problem. Tell her you have spoken to a lawyer, and were told that she must have it taken off your credit/find the necessary means to have it done or you will be forced to take legal action.