passive voice - She has been being mistreated

She is being mistreated. She has been being mistreated for five years.

Is the second sentence grammatically correct? Or should the being been be contracted to just been? I. e. She has been mistreated for five years.

She was mistreated. She has been mistreated.

If so, how to disambiguate it from the above formation? The original has a progressive connotation, and the one right above is simple.

I came up with the second sentence by converting was to had been and leaving the being as is. That's because that's what I do with sentences such as She is eating -> She has been eating (I leave the eating as is).