LinkedIn Marketing Services Manager interview questions

The process lasted three months, with up to 6 weeks going by without a response to my emails to HR. It consisted of three phone call interviews - two with HR and one with a manager on the team. After a rushed discussion from the back of a taxi, the manager said "you would be a great fit and we want to bring you in for a final round interview. HR will reach out in the next few days." Three weeks later after radio silence from them, I received a call from HR saying I would not continue in the process, without any feedback provided. It is extremely unfair to string me along, especially when I delayed accepting other offers, just to deny me. Very dissatisfied with my experience.