Does DataCap expire?

[ireney2022]

I got some DataCap and had it added to my Filfox wallet, and then found out that I had to have some filecoin in my wallet first, before I added DataCap. But it seemed that the DataCap was in my wallet and my Filecoin address was functioning properly. So I tried to make a storage deal, but couldn't find someone that wanted to make a deal, so I just put things aside for awhile. Then about a month later, I went back, and somehow, I no longer have any DataCap. Do you know what happened? Does DataCap expire? I couldn't find any explanation.