2017 MAZDA MAZDA6 Carry Handle Shell Base Problems

The car seat involved is a Nuna RAVA convertible car seat that was sent to the manufacturer solely due to a safety recall. I declined the self-repair recall option and requested that Nuna perform the recall service, which they agreed to. During recall servicing, Nuna inspected the car seat and advised in writing that internal Styrofoam/EPS foam in the headrest was missing or broken and that the car seat is not recommended for continued use and is not safety tested in that condition. Despite determining that the seat is unsafe, Nuna returned the car seat to me without providing a replacement, credit, or other safety remedy. The manufacturer has stated that the damage is unrelated to the recall and has refused to replace the seat, offering only a discount toward purchasing a new car seat. As a result of the recall process, I am left without a usable car seat...