Senzing interview questions

I was approached on LinkedIn without submitting an application. I conducted two interviews within 4 days of being contacted, and was told to expect follow-ups shortly. A month went by, which encompassed me thanking them, checking in twice, telling them I had an offer on the table, then telling them I had accepted the offer and I'm disappointed they ghosted me. After five weeks of complete silence, I was invited to a third interview, with no further commentary. Attached to the invite of the third interview was my ORIGINAL thank-you email from a month prior, none of my followups. During the third interview, I mentioned how odd it was that I was ignored for a month and nobody had mentioned that I already accepted another role. The interviewer expressed shock and dismay, claiming to be personally upset by this and vowing to look into it. At 9:30pm that evening, the person who originally contacted me sent me an email demanding to know if I had accepted the role I told him I had accepted weeks prior. I explained that yes, I had indeed done what I said I'd done. He replied by telling me that my experience was "a little out of scope" (remember, he was the one who approached me) and asked for my expected comp package without specifying a role or level of responsibility. I'm not sure what's happening over there, but the process was confusing and incompetent in equal measure.