so your purpose would be the requirement of a Non B visa that requires you to leave the country and you are unable to do so. In your email to the embassy put at the Top "information as requested". Attache your biodata page and last stamp. When you go to immigration take a colour copy and two black and white copies and tell them the colour one is the original. Don't tell them it was sent via email.
they should reply in a couple of days. If not resend it on Monday. There maybe a cut off date from Thai Immigration for applying also but that's not been announced yet.
just make sure you send them number 1 and 2. Last stamp if entry and a copy attached of your biodata page. I put at the top of the email "as requested". Came back in two days.
This is the correct email and procedure. They won't reply to any email and you have to supply the following. I didn't answer 3 and 4. I just stated my country of residence is Thailand. Got the letter two days later.
To apply for a visa extension letter email:
**************************************
Please provide evidence of:
1. Copy of the biodata page of your passport
2. Entry stamp in to Thailand
3. Proof of residence in a third country e.g. visa (if applicable)
4. Supporting documents relating to your long-term visa application e.g. marriage certificate, employment contract