PayPal Software Engineer ( Senior MTS) interview questions

The recruiter called and arranged for an interview. They pushed for 3 interviews in a single day but i needed a breather and had it scheduled for 2 interviews on day 1 and 1 on day 2 virtually. Round 1 was problem solving in data structures, can refer any letscode. Round 2 was architecture discussion on my current/ previous work and in general. Round3 was system design about online ticketing system. After a week did a follow up and got an email from some other recruiter that they considered someone else better. I was asked to contact in future for any requirement but i wanted the current feedback so that it would help me in other preparations. Alas, no reply from them. It was bad enough to conduct 3 rounds for all candidates and then shortlist with making us waiting but not giving proper feedback is so disappointing experience.