The best way to contact the Sangtiennoi gym is via Facebook here: https://www.facebook.com/sangtiennoi.sorrungroj
You will be messaging his wife P’Pook in English (simple English) or Thai.
(This website is run by a student of his and is only checked occasionally - so Facebook is the best option initially. Any questions regarding costs or bookings need to go directly to Sangtiennoi gym via - Facebook.)
If you are having trouble getting in touch or have other questions please let me know below.