Sorry to hear about your issue with BUSA but I have to say that I have not had an issue with their tech support when I've needed it.
You can get a clean set of plans and manual (I always like to keep an untouched set of plans around) at
1/4 Scale J-3 Cub Plans and Instruction Manual . It would cost you about the same to have a set copied at an Office Supply store anyway. Other than that, I can't offer any help as I don't have a BUSA Cub to refer to.
Bob