I didn't need the software "elsewhere" and I did have the installer. But the thing you're missing is that it was licensed for one and only one domain so even if I wanted to use it somewhere else, I couldn't. What money would it cost them to refund my money?! Are you talking about the discount fee and transaction fee? That's ridiculous but if that's the case then they the could take the $99 and subtract the ~2% discount rate fee and transaction fee (usually around 10 to 20 cents).
Yes I know the development is my bad luck, well aware of that. Obviously TKWT isn't obligated to refund the money but based on the situation, any good and decent human being would refund the money as it is the right thing to do. I provided them with proof of deletion (FTP deletion log as well as SQL database deletion), plus I completed their form and faxed it in.. I did everything they asked me to do in good faith that I would receive a refund for software I did not use.
Again, this seems to be a matter that is best discussed between the two parties having the dispute. You are not going to find a qualified mediator on a public forum, though it might be good to mutually agree to find one.