App Marketing Agentur interview questions

HORRIBLE. I had to wait 20 minutes and was offered only tap water. The interviewer sat down reading my CV point by point as if he didn't read it before. On the second interview he did the same and brought it another colleague to ask me questions. He then called me 2 or 3 more times, unexpectedly, to ask me how the interview was. After 4 or 5 interviews, I got an offer 35% lower than what I asked for and was pressured to give an answer within the next day because he was going on holidays. Despite my gut feeling I accepted the offer and absolutely regret it.