Just book via your guesthouse instead. We paid a lot extra to go via 12go/Yortday travel, but the service was very poor. The ticket said 8:30 departure and be ready 30 mins before. At 8:40 no-one had turned up so I messaged and was told 9:00-9:20. After messaging at 9:20 I was told it would be 10 mins. It seems to be the vehicle coming from Chiang Rai does the pickup, so you are also delayed by any border delays, sort of defeating the point of staying in Huay Xai, aside from the extra cost!