I've been through this same shit as both a buyer AND a seller and it is the sole reason why I no longer flip vehicles.
Bought a car once, met at a public place to do the deal on a Sunday, we were supposed to meet up that week at a bank or DMV to complete the deal. Douche bag would not respond to my calls/texts/eventual threats to get the title completed. The address on the title was no good, so with the help of my sheriff buddy I was able to find out where he worked
Showed up at his place of employment unannounced, he soiled himself when he saw me, and we went straight to the bank. I win.
The second time, I was actually the seller. This redneck mother lover came to look at a car I was selling at about 10 PM at night. Long story short, he gave me cash for the car and the title and we were going to meet the next morning to sign it over. Two months of excuses as to why he can't meet went by, so I ordered a new title for the car, took the new copy to the courthouse, and junked it.