I ordered a mobo from newegg that arrived defective. I only realized partway into building that one of the screws to secure the heatsink on the M.2 drive was broken. I immediately submitted an RMA replacement request. Just got an email now that they are denying it. What are the next steps I should take? The motherboard is the Gigabyte B550 Pro AC. They said:

"We apologize but after further inspection, it is determined that item has been installed. Any physical damage which has installation signal will result in return being denied. As of this moment, we are unable to honor this return and the damaged item will be returned back to you soon"

this is technically true... I put in the CPU and RAM. but once I saw it was screw was broken, I took everything out and shipped it back.

Please help... It was a $300 (Canadian dollars) board and I have no idea what to do