Sounds like a scam from the hospital, Myself my wife and 3 kids all got sick with covid when we returned from a trip and were in a pretty bad way for around 5 days, my wife went through all the correct channels and we were given medicine, tests some other equipment such as heart rate monitors and temperature tests and of course being Thailand a lot of paperwork, not 1 baht was asked even from me the Farang. For reference this was in Udon Thani.