Then they did something wrong as personal goods are exempt from import duty when shipped and arrive within the first 6 months of your relocation. Talking from personal experience a few years back. I doubt this rule has changed since.
You can obtain an international drivers license as a foreigner issued by Thailand. But you need to carry the (Thai) 5 year license. You can't get it on your first 1 year license.
You can also just book a cheap flight with a budget airline to one of the neigboring countries. As long as you show a flight out of TH it's okay. Don't need a returnflight to where you come from.