StackAdapt Performance Marketing Manager interview questions

Very lengthy process for an intermediate level position. In total I completed an introductory call, a case study (they claimed would take 2-3 hours, but in reality would take 5-6), and 3 other interviews. The interviews were fairly standard, but there was certainly some overlap in questioning. The most disappointing part was after spending approximately 15 hours in interviews and case studies, I had to contact them multiple times to receive notice that I would not be receiving an offer. They also offered a feedback call, which I requested, and they have since ghosted me.