What should I do if a gas station refuses to give me my change?

I work midnights so I drink in the morning, it is my bed time. So I stopped at the usual gas station around 7:30 am. I paid with a $10 bill, don't ask how I know, but I am 100% confident it was a $10 bill. I got two shots and it was $3.23. So she gave me a few bucks back, didn't bother looking and threw them in my pocket, she gave me no change.

As I got home I actually took the money out as I was about to put it in my wallet, and there was only 2 $1 bills. I thought wtf I paid with a 10. I was about to let it slide but it's like no I work hard for my money I might as well go back up there and clear it up before it's too late.

I drove back up there, a half hour drive btw, the gas station is half point between my house and work. I said hey can you check I believe you shorted me in change and explained what happened. She argued with me saying I paid with a $5 bill. We argued back and forth and I finally said I didn't even have a $5 bill. Sje asked what she wanted me to do. I said check the cameras I see you have a ton here. So she rolled her eyes and said wait a second

She called me right back over with a receipt with my total and that I paid with a $5 bill. I don't even think she checked the cameras. She told me she always pays attention with money people give her and she had to be right. At that point I was more pissed than anything but I knew arguing was pointless. I said sorry I must be mistaken and left. Half hour drive back home.

Now I bought two overpriced dollar singke shots for 8 bucks. And she wouldn't give me my money back. I am 100% certain that I paid with a $10 bill am I just screwed out of my money? Now I don't even want to go back there. She did say they count the register at the end of the day and if they have extra money she will credit me but I feel thats bs and nothing will come of it.