Recommendations for Excellent Pasatai Teachers in BKK?

Hi, I've been in Thailand for 3 years now on a retirement visa. I've made an effort to study pastai at a private language school (100 hours), the AUA program (15 hours) and have tried several people claiming to be professional tutors, but none of them had a systematic technique. Not finding the right support has reduced my enthusiasm for learning the language, but i still wish to study pasatai.

Can anyone recommend a teacher, preferably a university trained one, whom they have had a positive experience with in learning thai?

Also, any online sources that you recommend?

Thanks to all