I have send back my Pixel 5 Trade in for $500 off my new Pixel 6. It was in mint condition so hopefully no issues receiving the full credit. Here in Canada its handled directly by a third party return center not by Google Canada.
I dont know about Verizon but i got a email Google giving the 405.00 for my pixel 5 trade inVerizon taking their... extremely sweet time on both my sets of credits. Getting a manager on VZ Business has been absolutely impossible.