First I would consult an attorney by phone and ask whom is responsible for the mess. My guess would be Day’s transmissions.
Second I would send a certified letter with a signature required letter explaining that you tried to reach them several times unsuccessfully and that the trans went out on such and such date…etc and that you also called the repair shop that is now out of business and they made it clear that this is the party whom did the repair.
In the letter I would enclose a copy of your receipt too.
I would tell the man he has 48 hours upon reading the letter to make good on the warranty or you are going to the next step…that would be to call the better business, call the local news (sometimes they have people who check this stuff out for fraud.) to let them know about this man who is ripping off the public and I would also contact an attorney…
maybe if you put some fire under his butt he will work with you..