I just went through this, and ups is by far the worst of all the delivery agents.
Anyway, I am in Pattaya, they finally sent me a paper and I had to go down to the laemchabang customs office and register ups as a broker. The reason they are asking for your passport is because they can do the registration for you, but you can do it yourself at whatever customs office is in your area. This is after I sent them details of the Amazon order, passport copy, copy of the tm card and visa.
Mine took longer because they sent the letter I needed to register to the wrong address.
Ups is by far the worst of all the delivery agents to deal with.
It takes time, but I would check out the closet custom office in your area, and register for the paperless thing.... Which takes loads of paper to sign, ironically.
Ask ups for the letter if you want to register yourself.
Good luck, it will eventually be over.