Had an initial call with their HR department, the hiring manager was very specific about the use of a ESP and, since I never used it, it was a very short call. She called me a few weeks later, they couldn't find anyone for the role and were now open for candidates without experience using that ESP. We had a phone interview and never heard back. Very disrespectful not to email candidates back after they spend their time researching and preparing.

I was initially offered the job, and given an offer letter. This was later retracted, after I’d signed it. This is really poor form. Don’t interview people of you’re not willing to actually hire them?