@John ********
I went to the AIS shop in Terminal 21 in Bangkok. I explained what features I wanted, and that I wanted a monthly plan that I could easily top up. They sold me a 300b / month plan that gives me 5G unlimited data (I think) etc. I go into my Bangkok Bank app and periodically top up my AIS account with a transfer. They send monthly reminders when they are about to bill me, and I can call a number and it will show me my current balance. Given your name, I assume you live in Buriram like me, I go to the AIS shop in Robinsons if I have questions or need assistance with something. I note that 5G is not widespread in Buriram.