Band Stole My Original Merch Design - Do I Have Grounds For A Lawsuit?

So I am a teenage girl with a fan account for my favorite band. Two years ago, I jokingly made a merch design that was intentionally bad to poke fun at the band, posted it on Twitter and got barely any likes and thought nothing of it. A year later, that same merch design- like a carbon copy- was officially released on the band’s website and sold on tour dates as well. Obviously I was like well that’s crazy because that means someone saw my tweet and made this right. But no, it’s more than that. One of my Twitter mutuals had a friend who works for UMG and was in a group chat with the lead singer of said band. He had send a screenshot of my tweet with the merch design to the group chat, but with my name cropped out, and said “this is my original mockup.” I have proof of it. Even though it’s all very silly, the lead singer of my favorite band literally did steal my merch design and made tens of thousands of dollars after it, with me getting zero credit or royalties. When this all happened, I posted about it, which led to a band manager messaging me and offering me some free merch and guest list to shows, etc, pretty much to keep me quiet about the situation. He even offered me a meet and greet. That was more than enough for me then, but it never followed through. About 6 months later I was sent a pack of about $90 worth of merch and that’s it. Honestly this whole thing is silly, but now I’m a college student who cant find a summer job and have no money to my name. If I actually have grounds for a lawsuit, not only would it be kind of hilarious, but I could make some money?? Just want to know if it’s even an option lol