According to the website, they are open, and you just said they have a working number.
Call, ask for the guy and have them fax you the waiver.
If it was me, I'd go grab my camera, and go film the place being closed just to have evidence to back my position. Then if I am wrong, I would just pick up the waiver while I was there.
You are trying to weasel out of this fight, admit it.
Just back out now, and walk away, because you know darn well, Rudy is going to be there, he's going to film the venue, inside and out, and he's going to have himself filmed that he's waiting for you and you didn't show.
You might as well save yourself that embarrassment by officially backing out now and admitting you are scared to fight him.