@Marius *********
I have chatted with Tod.... Suggests that you go to Savannakhet Laos and apply for a Thai tourist visa...
Be sure to use an experienced border visa run commercial company from Chiang Mai or Bangkok..... as they know what you need to do and what the Thai Embassy is doing.
As you are in PHUKET... Fly to Chiang Mai and go from there to Savannakhet.
There is NO new land border VOA Visa on Arrival available to you.