Springer Nature Sr Software Engineer interview questions

I applied from an online platform. The recruiter contacted me via email. 1- Introduction Interview: A straightforward skype interview with the recruiter about past experiences and current role. They also asked for my salary expectation. After that, the recruiter sent a take-home project to complete in a week. 2- Take Home Project: A set of commands to draw some shapes like canvas, rectangle, line etc. in the command-line interface. I completed the project and informed the recruiter but the recruiter was not working for this company anymore. I sent email to the other people in the company but did not have any response for more than a week. After than, a technical manager sent me an email and told that they want to continue to the process with me. 3- A Remote Pair Programming Session : Pair programming session with a team lead and a senior developer. We went through my implementation in the take-home project and asked to add a new feature to this project. They also asked some technical questions. 4- The manager sent me an email that in order to make a decision they need to re-ask my salary expectations and I sent my expectation as I told them in the first introduction interview. 5- They became unreachable for more than 2 weeks. They did not reply any email. 6- A new recruiter sent me an email and told that they want to make another interview with the team lead and the manager. We had a google hangouts interview, they asked technical questions and I also askes questions about their working environment etc. 7- We had another interview with the last recruiter. She told me that this is an informal interview and just want to learn my experience in their hiring process. She also asked for my salary expectation for the 3rd time. I asked for some photos of the office because of all the interview process was online. 8- After one week the recruiter sent me an email and just told that the made a decision not to hire me. She did not provide any explanation just a simple email. I asked for the major reason because we had many many sessions and the whole process took more than 2 months. You should at least give the reasons to the candidate if you go through all the stages in the process. 9- She sent me an email and told that the reason is my salary expectations. This is unbelievable because as I mentioned they asked my salary expectation for 3 times from the beginning. As a result; - The team lead and the senior developer that we had pair programming session were all nice people. - The hiring people are not too much professional and not aware of the candidate and the process. I believe you should at least provide a reason if you made a decision not to hire a candidate that passes all the stages. - The main thing they are looking for is a cheap alternative. - I told my salary expectations 3 times but they did not tell that this is over their budget until we complete all the stages. I believe this is unprofessional