You can post any problems you're having to the Marketplace Customer Service forum and make them aware of it if they aren't already. Or the Community Center forum for more general issues not specific to the store. Just be sure to give as much detail as possible - which browser, etc. Admin are usually pretty quick at looking into specific issues when brought to their attention.

I would do that if I though something might actually be done about it. Unfortunately, what typically seems to happen here is that you report a specific issue with details and screenshots, a friendly forum moderator acknowledges your post, and then nothing.