Oregon Screen Impressions interview questions

I interviewed for a position with OSI and even though one of managers in the interview seemed extremely disinterested in me, I thought it went well. They mentioned they continue interviewing other candidates and would follow up in a week. Three weeks go by and the managers never contacted me even with a hand written thank you letter and two follow up emails. I obviously didn’t get chosen for the position, but I’d rather be rejected with dignity than ghosted. I do think this was very unprofessional.