Mangopay Senior Java Developer interview questions

I got an email saying they were interested in interviewing me, so I booked a time through the same email. The interview itself started with someone from HR, who we talked about my background and what I was looking for. They gave me the last 15 minutes to ask any questions I had. Unfortunately, I couldn't move forward in the process. They sent me an unprofessional email saying I couldn’t start working immediately, even though I had proof showing that I could, having a job contract and my job-seeking visa. After that, I tried reaching out to other people in HR for clarification, but no one got back to me or helped resolve the issue.