You've been trying to enter repeatedly as a tourist, ( but trying to live in Thailand because you've got a girlfriend?)so that's why you've been stopped.
When I opened my bank account they asked for UK ID card and passport. We don't have ID cards ( not since just after the war ). I gave them my seniors bus pass, which had my county's govt address on it and my photo. Convinced them it was equivalent of an ID card. 😆