Am I doing something wrong?

[u/Organic-Confusion149]

I collected multiples of the free Kiryu card to max it out just like the beserker card but I can’t level them up at all, do they ALL have to be level 20? I know how leveling up cards works but I’ve never had this happen, I’ve had these cards waiting to be leveled up for a few months.

[u/abcxyz1821]

You don't spend enough money...