Hello. I have a question that I don’t manage to find an answer to. The lawyers we contacted are asking exorbitant fees for the services that I don’t think we need in our case. 
Maybe someone had a similar situation? 

In brief: back in March 2020 Thai Ministry of Tourism revoked the free visa entry to a number of countries including ours based on high covid cases. We flew to Thailand without knowing we needed a visa to enter. The airline didn’t know either as the law was passed a few hours before our flight. On the border the custom officials stamped our passports “denied entry to the Kingdom as per Immigration Act 2522, section 12(1)” which practically means that we tried to enter the country without a valid passport/visa. We were sent back on the first flight. We did not have to pay any fine. 

The free visa entry has been reinstated since then for our country. We now would like to travel to Thailand but unsure whether we can enter without being stopped/sent back/arrested

19 minutes ago, Nadyalav said:

The free visa entry has been reinstated since then for our country. We now would like to travel to Thailand but unsure whether we can enter without being stopped/sent back/arrested

You won't have a problem. Even if questioned the dates will line up with the border closures and they will understand what happened.

 

If you are that worried about it, drop the Thai Embassy in your country an email explaining what happened and have a printout of their reply handy if questioned at arrivals.

You were not "blacklisted", only denied entry. This can happen for a number of reasons, and I believe would only cause an IO to possibly inquire about why. If you meet all of the current requirements, there is no reason you would be turned back, but I cannot be certain. I cannot imagine that you would be arrested. It should be possible to find someone who can give you a more definitive answer for a not outrageous fee.

I wouldn't be in any rush to ever return to a country which previously denied me entry.