This is a further update on this story, summing up what I've gotten from Thai news:
Sia Boat has proceeded in bringing charges against Fahwanmai (the fighter) and Udom Chalee (who paid for the thrown fight), which according to Thai law carries a prison sentence of no more than 5 years, and/or a fine of no more than 100,000 Baht (around $3000). Fahwanmai has given an account of how contact was first made with him (it's unclear, but sounds like there was a middle-man in this deal) by a man purchasing a food item that Fahwanmai sells and ships. The man purchased 2400 Baht worth of the food item and overpaid for it with a total of 5000 Baht. On his next order, he said not to waste money packaging and sending the goods, he'd come pick them up himself from Fahwanmai. They spoke on that day when he visited his home, casually, the man asking about any upcoming fights and how Fahwanmai's training was going. He didn't mention any deal at this point. Sometime after this, he contacted Fahwanmai again and told him it would be "better if you couldn't win" in his upcoming fight against Lahnyamo, suggesting he fight for real for 3 rounds and then go down in the 4th, which is exactly as it happened. According to Fahwanmai's testimony, the contact said he'd pay 30,000 Baht upfront (which he transferred on the day of the fight) and the remaining 470,000 Baht after. If Fahwanmai decided not to accept the deal it was "mai bpen rai," (no problem) but he couldn't tell anyone about the offer, carrying with it a threat that he knows where Fahwanmai lives, since he'd just come by to pick up the order of condiments he'd purchased in their second meeting. So, initially Fahwanmai had said he took the deal under threat of physical attack and not for the money, but in his testimony here he's claiming the threat of bodily hard was not for not taking the offer, but if he told anyone about it. After giving his testimony he begged Sia Boat to not send him to prison because he wants to work to take care of his mother and grandmother, and even asked for a now third chance to fight for Sia Boat again. Comments online have been making fun of this request, some quite harshly. Dieselnoi joked that if Sia Boat were to give Fahwanmai another chance he'd do well to change his fight name to "ai dek hia" which is a pretty rude way of saying "Little Bastard." The case is ongoing and Sia Boat has made no official statements other than that he is pressing forward with the charges and his interests are in protecting the Muay Thai Community from anyone who seeks to do it harm.
above, Fahwanmai giving his story of events
above, This photo is a television interview with both Fahwanmai and Sia Boat. Fahwanmai is asking for forgiveness and to not go to jail. Sia Boat said that prison is his karma for the choices he made and for the matter of fighting again, it would be a very difficult ask for anyone to trust him again. He has admitted to throwing 4 fights in his career as a fighter, fighting since he was a boy.