Same problem I had, thinking you can get visa for the amount of days you want !! You can't, only 60 day tourist visa from the thai consulate, I was told at the embassy i needed to go to immigration to get extra 30 day but maybe mau, I didn't listen, ended up overstaying to the amount of 20,000฿ ,
Only because of tod's good wisdom, I got off lightly 20,000,฿ fine and 1 year ban( the red mark still causes problems and cannot be removed)