I have bookerd with Chalwa travel in Patpong. I had a good service by them.
They are open during office hours. They also gave me a quick responce by mail. I faxed them my credit card number and I pick-uped my ticket when I was in bangkok. ^ Another compagny in the area is Royal Exclusive travel on Silom Road 191. It is in an office building near the Dusit hotel. With them I booked some hotels around Thailand ^