MuleSoft interview questions

First, I had a phone screen with the recruiter, then I did a technical phone interview with group tech lead. Phone interview questions are performance area related, then followed with a coding question. Everything went well and I had onsite interview with 4 people at SF office (3 in person and one phone call). First round is a ~2hr (or 90 mins, I don't remember) pair programming excise, the problem is not performance area specific, but the difficulty is medium level, but with corner cases. The engineer who did pair programming with me was patient and professional, just like my co-worker! Other three interviews are a mix of technical and behavior questions. In general, my interview experience is great, the interviewees are nice and my interview experience is great. Last but not the least, my recruiter is very professional and helpful, he accommodates my schedule for phone calls since I am in a different time zone, and he always provides updates about my interview progress, and he helped me get an offer approved in a short amount of time.

Process was good. I cleared it but it took 5 months. after three rounds they told me VISA requirements needed me to travel to EU and UK and I have eligibility only in EU. After 2 months they reached out asking me to continue the process - telling me that their requirement have changed and they only need EU travel eligibility. Called me to London, gave 4 interviews. Cleared them. Was given a feedback that its very psoitive. Again reached out saying they now require EU and UK eligibility. Nightmare! I put in so much time effort. Is this even ethical and professional? Money also hasn't been refunded for travel to London