My first response is "I don't believe that, and that sounds odd", and didn't respond back to that, intending to completely ghost him until he comes back with a proper explanation to that statement. How busy can a person be to not be able to arrange a call all day.

My second thought is perhaps I should ask further, and try to arrange a "call". I am always confused what to feel about the slightest inconvenience, as I don't trust my feelings.