AITJ for refusing to cover my coworker’s shift after she lied about why she needed off?

I (26F) work at a busy restaurant, and like most places, swapping shifts is pretty common. I don’t mind helping out when I can, but I also believe in fairness.

Last week, my coworker Lisa (24F) begged me to cover her Friday night shift because she had a “family emergency.” She sounded really stressed, and since I had no big plans, I agreed.

Well, Friday night comes, and guess who posts Instagram stories at a concert? Yep, Lisa. Not just a casual dinner or some low-key event—she was front row at a sold-out show, dancing and having the time of her life.

I was pissed but decided to let it go. Until… she asked me to cover for her again this Friday. This time, she gave some vague excuse about her grandma needing help, but after last time, I wasn’t buying it. I told her, “Sorry, I can’t. Hope you figure it out.”

She got annoyed and said, “Wow, I thought you were cool about switching shifts. I covered for you once, remember?” (That was eight months ago, by the way.) I told her I didn’t appreciate being lied to, and now she’s sulking and acting like I’m the bad guy.

Some coworkers say I should just get over it and help out, but I feel like if she lied once, she’ll do it again.

So, AITJ for refusing to cover my coworker’s shift after she lied to me?