Unfortunately it is a learning experience. I had a fuel tank leak on one model, but not as bad as you have described. I was able to restore it and fuel proof it somewhat. I now always coat the fuel tank area with thinned epoxy, even if it takes the brush and extension as referred to above. If it's indeed ruined, someone may have a decent fuse remaining.

I have just thrown away a Hangar 9 supplied fuel tank and most of the hardware. Absolute piece of junk, but I thought Sig was one company where you didn't have to throw away the hardware or anything else that came with their products. I would phone and or email them. I was fortunate with an Eagle II ARF a long while back when Goldberg was still Goldberg. Remember they would only have to supply you with a fuselage and they may have one lying around.

I can't tell you to continue, but I've been at the stage you're at and I'm still flying.(along with several thousand others)