Problem with Commander Lilith DLC, Help is appreciated

So a while back I had heard about the Commander Lilith & the Fight for Sanctuary DLC and saw it on my steam library’s “what’s new” about a week or so after it came out (I was playing Borderlands 3 on Xbox at the time but I do remember checking steam because of hearing about it Somewhere). I could have sworn that I collected it successfully, But now when I go and look at Borderlands 2, thinking about maybe starting it up again for a good time with some potential new friends and possibly play it all the way (on PC at least) this time, I see that I don’t have it.
Now this could potentially be me mis-remembering but I can remember decently clearly claiming that DLC during the time it was free(As in, actually seeing it In my library and not just looking at it in the store page). I don’t know what could cause it to have disappeared(possibly an error where it didn’t claim correctly? Maybe it forgot I already owned it when it moved from free to paid?) but I don’t want to buy the DLC if it is indeed a weird error that can be fixed, because then it would just be me paying for content I probably already own and that’s silly.

It was released in June 2019, so 3 months before BL3 came out.
Anyway, you should have some purchase confirmation, even for free item so check your mail and maybe contact Steam support.

Must’ve gotten the dates swapped in my mind. Either way that purchase confirmation thing is a good Idea so thanks. Ima go try that out.

Yep Seems like I must’ve not claimed it somehow. Ah well, at least it wasn’t Taken from me. So when I buy it I’m not doing something silly.
I am a little upset that I managed to somehow not get it when it was free but at least it isn’t a case of “had it and it than it got taken away” though I have to admit I am still a bit salty that It didn’t give it even though I can remember claiming it.

Maybe you had it on other platform? I remember something that for one platform it was released way later, not sure if it was Stadia or something else, but it was also free for a month.