You've overwatered them. By soaking them and after drying, placing them in jars (!), you've cut off any air circulation. Yes they sound mortally wounded. Start fresh with new ones and hang them where there is good air flow (preferably outdoors). Ionantha does not take well to constant wet feet, misting once a week should suffice.

Oh no, you've totally misunderstood! When I said jars... Well, I guess fish bowls would be more accurate? They're wide open! I have never closed them up in anything, I know better than that!

Like I said, 4 of them are totally healthy. Someone from a greenhouse told me to soak them for an hour at least once a week, so that's what I do, then let them drain and air upside down on a cloth before putting them back in their containers.

If it works, I'm trying to attach an image of how I have them displayed. As you can see, some are totally healthy.

Jars are for jelly and bowls are for fish, not Tillandsias. They need complete air circulation. Unless your temperatures areconstantly in the 80's a cmplete soaking once a week is not necessary. Misting a few times a week will do.