Is this still an issue? I have looked in our database and I can only see that your account should be considered as a "premium". We are aiming to treat "Charter" and "Premium" the same way, and the related changes in the API should be handled.
I haven't heard about his exact issue from anyone else, so we don't have much to go on right now. Sadly. I have tried to run the related functions with your account-id and they do return that you are premium which is confusing.
If it's still an issue, could you try logging out from the site and re-authenticating?
PS! In our early days we didn't know about Charter, and back then we did not treat you as Premium, but that's many years ago.