Suspension noise and local dealership

Well, talk about totally unimpressed, disappointed, frustrated, and downright angry!
The "higher rated" of the two local dealers (I purchased the vehicle out-of-state since both dealers cannot get allocation 'cause they don't know how to sell vehicles) totally wasted my day. They "test drove the vehicle and found nothing." The test drive was all of 1.6 miles (I had taken down the mileage between the time I left it with them and the time they said all was completed).
So the thumping sound remains. Additionally, I have a spring squeaking sound coming from the left rear each time I enter or leave the vehicle. Sometimes I can hear it just moving inside the vehicle while it is in park.
So much for Nissan USA trying to get this thing fixed. No wonder they have a complete manual dedicated simply for consumers dealing with various state lemon laws. :twisted: