Apply for the express Myanmar evisa and you’ll be okay to cross mae sai. It says within 24hrs. So you should get it before they close tomorrow. The border is not closed, you just need a visa.
no issues here, i am the OP from that post. haven't had any issues since that day, i think the IO was just having a stressful day and wanted to ask some additional questions. i have a non-o M thai spouse and a WP i have had no problem with labor. i think immigration and labour just do not talk with each other so they do not know each others rules.
if you are still living at the same residence and have your previous one still stapled in your passport, you just need to bring that and tell them that you left the country and came back - that is how it works here in chiang rai, cannot confirm for other offices.