I work with a STEM education nonprofit. A few weeks ago, I reached out to a local science museum hoping to establish a relationship and work on joint projects. I heard back from one of the people there. He mentioned that he'd had dealings with the nonprofit in the past (before I got there) and the experience was not a positive one. However, he said he was willing to meet on any one of three consecutive days during the month.
I reached out to the nonprofit president who said he was available on any of those days, so I followed up with the museum representative via email and did not hear back. I left him a message on his voicemail the next day. He returned my call on a Saturday afternoon from what I assume is a work cell number, but I was unable to take the call. He seemed fairly irritated about "playing phone tag", and asked me to pursue further communication via email. I returned the call in 60 minutes but got his voicemail (I had not had a chance to check my voicemail yet). Since then, he has not responded to any of my emails (or read them, as far as I can tell).
Is this a lost cause at this point? I have the name and phone number of his supervisor. Is it worthwhile to try going through her?