Move on.
I understand the risk for both sellers and buyers, but anybody who charges ridiculous restocking fees should be avoided. 5% or 10% might not seem like much for small ticket items, but if you’re buying a $10K item, that is a lot of money for pleasure of opening a box. For those asking 20%, I have some choice expletives reserved for them.
The kicker is that many retailers will turn around and sell your return as a new product (depending on the condition) versus selling it a discount as an open box item.
That said, relationships are important. Build a good faith long term relationship with a dealer and the both buyer and seller will be rewarded. You will usually have a person and phone number to call. It's usually not an internet based relationship.