There are only four ways to avoid conscription. Medically unfit, Education at university or college, attending a draw and not getting picked, or an illegal bribe to an official.
Sounds like you only have two options:-go through the draw process and hope for the best (up to 50% chance of being picked), or the bribe.
A friend of mine's father stumped up for the bribe and he left Thailand to live in the UK, joining the RAF.