general problems of the 1998 Nissan Maxima

I have tried 4 different car seats and still do not fell safe with the fit they have in this car. The seat inclines and without a towel or something under the car seat you can not install a rear facing car seat. I do not find a towel very secure since it slides and the seat is therefore not in place for long: that is not very safe. I bought a special car seat with a rear tether that can anchor from the rear of the seat to the frame of the car, but the Nissan service center told me they could not install it; they didn't want to assume any risk if the frame could not hold the seat in place in the event of an accident. Had I know I was going to have such a problem, I would have chosen a differnt car; one in which a child seat was more secure in.