Can’t change payment methods

So the only person who made himself a family organizer doesn’t have an iPhone and I’m not in contact with him anymore—I’m only with the other person who’s in my family thing.

I’ve been wanting to put my own information on so that I can buy my own stuff. I won’t be able to contact the organizer due to issues that are happening outside of him not having any iPhone.

Along with that I’m sure he’s list that card information, I’ve just been very irritated, and I want to buy things. Please help me. :(