Accelevents interview questions

It was a pretty informal process. I had an interview with the hiring manager, which I thought went well but I never heard back. I followed up multiple times and did not get a response.

I had three interviews, one was a phone screening with HR and then two back to back with others. After the phone screening I received an email that said "We're excited to invite you to a first round phone interview!" which was confusing since I had already done that. I followed up and was told this was actually for the second round. I scheduled my next two interviews which I felt okay but not great about so I wasn't surprised when I received a rejection. The next day I received an email that said "our hiring team reviewed your application and did not select it for further consideration at this time" with zero reference to any interviews. It also came from the generic Accelevents email account, not the HR person I had been speaking to. The wording felt so odd that I first thought it was an automated email that was sent by mistake. If I'm not the right person for the job, no problem at all, but an automated rejection after THREE interviews that doesn't even reference the fact that you interviewed at all, felt cold. After the rejection, I sent a nice follow-up with a thank you for your time note and asked if there was any feedback for me so that I can improve in the future. No response from either person.