What are the best options for applying for a DTV visa and Muay Thai gyms in Phuket?

I once had a problem with not canceling my ED visa and then wanted to fly back home. At the Bangkok airport, the female customs officer completely freaked out and started yelling at me. She then disappeared into the backroom and came back, cursing and screaming. The whole thing lasted about 20 minutes, and in the end, she somehow canceled my visa. As you can imagine, I won't forget this. I can't say whether a non-cancelled ED visa will affect your DTV application, but as a precaution, I properly canceled my ED visa before applying for my DTV visa. I think that's the proper process.