I re-entered Thailand via BKK on my yearly extension of a Non-B visa about a week ago. After getting back home to Chiang Mai, I noticed that the official has written the wrong date on the "until.."-part of the entry stamp by a month.
Do I have any other options than returning to BKK airport to get the mistake corrected? Tried calling Suvarnabhumi immigration but nobody picks up the phone.
ps. Yes, lesson learned, always check your stamps immediately after receiving them.
TLDR : Answer Summary
If you've received an incorrect entry stamp date in Thailand, you can get it corrected at any immigration office if you entered by air, including the main immigration office in Chiang Mai. If you entered via land, you will have to go back to that border. It's advisable to immediately check stamps after receiving them to avoid any potential issues.