How do I change my security questions

I am trying to buy something on the store and it says I need to answer my security questions, which does not exist by the way, I have never had one, but it keeps asking me to fill them out anyway, and I can't create one, and there isn't any effective way to get it changed because it doesn't even exist. I have spent hours trying to get this fixed and no one will give me any real answers. They just keep telling me to do everything I have already done, or tell me something that has nothing to do with it. I can't just email it to support because apple won't let you do that for some reason, and no one seems to ever give me a good answer. Is there anyone that actually knows how to fix this? I am getting really frustrated with this terrible support!