@Dave *******
IF you got the 30 day extension of stay at your local Thai immigration office, then no problem.
Many if not Most Thai Immigration offices do require a TM30 on file with them.
Which Thai Immigration office did you use?
And that's why I always say ASK your Thai immigration office for their requirements for the 30 days extension of stay.
And it's possible that your hotel or property owner did file a TM30 when you ARRIVED. It's their responsibility. BUT IF they don't, then you can self file IF your Thai Immigration office Allows