@Steve *******
a "visa" is a title which allows you to ENTER a country.
A stay permit is a title which allows you to STAY inside the country.
After you ENTERED, the visa is void.
You are in the country with a stay permit.
And in case Immigration extends it, they will extend your stay permit.
Immigration cannot extend a void and "USED" visa.
I sincerely hope the correct termination is AS CLEAR AS MISSISIPPI MUD now
Thai Immigration wrong termination, is not my cup of tea, it's theirs . . it's on THEM !