Trying to get backer stuff back

I donated to the Indiegogo campaign for backer awards, and it worked out perfectly fine, I got all the stuff I was supposed to get in-game. The game wasn’t in a playable state for me at the time though, so I stopped playing for a few years and after coming back my backer stuff was gone, I only have my legacy donor stuff from gmod tower and the name I used for backing is in the lobby. I’ve been playing for a while without it now but I finally got the courage to post about it here. Is there anything I can do to get it back?