There are a lot ways to change your money to thai bath.
Also you can use the ATM Cash machines – in front of every 7eleven you find different.
If your Maestro Card is not working on one ATM, try another ATM.
Be warned – if you choose directly – transfer money to bath, it happend to me one day that at one ATM show me 35.67 Bath for 1 Euro and another one 37.15 bath. Offical have been 38.21 Bath for 1 Euro that day.
The Fee is most 220 bath for one time take money (Most support only max. 20.000 Bath)
Also the Exchange services are different.
My advise if you have cash: Go daytime inside a bank – there are a lot – and change your money there, you get most the best rates there (ATM is different)
To get the daily rates – install Superrich APP (Android and iOS) on your phone – with this you can check if someone try to cheat you 😉