Translation:What was she saying?
For anyone wondering, 申す（もうす） is the 謙譲語（けんじょうご, humble language) form of the verb 言う（いう）. More info about keigo here: https://en.wikipedia.org/wiki/Honorific_speech_in_Japanese
This was my initial assumption, but reading these comments, I don't think so.
何を言っていましたか is "what were they saying?"
何と言っていましたか is "were they saying 'what'?"
Slight difference, but if the と particle is really a quotation marker, the 2nd seems like how it should go. If not, then how would you say that?