This 300baht was mentioned before covid as a insurance cover for bad ferang that don’t pay hospital bills. It all gets obscured as no real explanation is ever given or follow ups just a constant grabbing for more tourists money
Stop stop stop people with half information that not good please ignore above comment where as they are not wrong to a degree there is far more information needed & more conditions please do your research touch out to embassies & take everything with a pinch of salt
2 options keep trying at other banks or branches don’t accept answer from 1st person that greats you explain you are retired not need work permit. It took me 10 attempts over 2 days & finally a manager heard me pushing issue & processed application & sent to head office & opened 3 days later. 2nd the letter from embassy is a letter of residency & can get the same from immigration you need a rental agreement & they will normally post to you within 2 weeks. But go immigration with partner to get information