my founders cape is gone

I used to have the founders 2019 cape like 1 year and 6 months ago and at first, I thought nothing of it and I thought it would come back but it didn't and the only cape I have is the pan cape and yes I did get the founders cape from the store so how can I get it back and when I got the cape i was on ios but now I play on windows 10 and I don't have it.