Changing premium tabs to merchant

It is happening to me as well. I have 11 premium tabs and cannot convert any. Please fix as soon as possible. I don't care for that "upgraded tabs don't count" as I have the video screencap and that information was not available, therefore it's malpractice and even sue-worthy. I expect this situation to be resolved favorably without the need of any legal repercussions.

How can I upgrade my quad tab into merchant ?