the answer that came back to me was "ya'll been at work? what in God's name is this. "Ya'll is a slang here in the U.S.....please check ypur English translations
We accept that (even if it's colloquial, at least it's some way to distinguish singular and plural 'you'), but it's absolutely never a starred option. But it seems we missed the 'most normal' option in one word order, so perhaps that's why you got it.
"You have/had been at work?" will now be accepted, as it should.
"Ya'll been at work" would not be accepted, it had to have either "have been" or "had been".