I can’t help you with this. Our policy is that we don’t do account specific actions. We want to provide free hosting in a sustainable way, and use what little resources we have to improve the service for everyone. I don’t believe cleaning up folders people no longer need on specific accounts is a good way to invest these resources.
If there is a bug in the platform, we will fix it. If there is a workaround, we will offer it. But if there is something that can’t be done by you, we’re not going to invest scarce staff time to do it for you.
Yes, the undeleteable folders are a known limitation. There is no way to delete the folders, so you’ll just have to ignore them.