Wunderman Thompson Technology interview questions

I had 3 interviews, an initial screen call with a recruiter, 1 to 1 interview with a Creative partner and 1 to 1 with the User Experience director. At all stages I was fairly treaded, at the last stage with the UX director, he gave me direct and constructive feedback on how I could improve my presentation to the position. In the end, I got the job but for the Junior UX position which I refused because of the salary (35K year) when I was applying to be a middleweight with a salary of 55k year. The UX director also said that I'm a middleweight and they only hire designers from other companies like Spotify, BMW, EPAM, EY, AKQA. Why should I accept a junior Ux position if the Head of UX said that I'm a middleweight?

Stage 1 - Application confirmation and initial screening using 1-1 questions with a recruiter. Stage 2 - Submit outputs from a prescribed exercise. Stage 3 - Pre-recorded video interview, answering specific questions on camera. Stage 4 - Invitation to one assessment day; involving group task, panel interview and more interactive exercises to judge skillset and area knowledge.