Going by case photos, it looks like you should be able to slide it out backwards. You should be able to to put pressure towards the case, on the top or bottom edge of the side panel, and then push against (like sheering) the top or bottom panels, trying to slide the whole panel out towards the back.
If there's room, you could also try using a screwdriver, parallel to the front panel (just push it back, not try to pull it out). If there's enough room on the back, where the side panel screws in, you could try carefully twisting a screwdriver head in there to loosen it up (probably not worth trying if there's more than 1/8" of space).
Then, look to see if anything has been bent, straighten anything that has, and try again, this time being careful to make sure the panel is not bulging out anywhere.
I doubt you're even part of the first million people to have that problem with such a case.