Can a job deny pay your entitled too after quitting?

I took a vacation March 4th-12th I was suppose to be paid for the vacation however my manager forgot to put it in the system. I just quit on Saturday without notice. Theya re talking about not paying me for that vacation now. Curious if they could legally do that or not ? Also, on March 3rd i traveled to another store to help them out and they never paid my mileage to me. They are also saying i can no longer receive that money.