Zions Bancorporation interview questions

I was called in for an interview and without prior warning, I was given an Excel assessment. This company requires a high level of Excel experience. The assessment I was given was to create a spreadsheet with loan amortization formulas and I had no clue how to do it. Although I have some experience working with spreadsheets, I am not very experienced with formulas. I politely walked out of the interview after the interviewers left me in the room to do the assessment. Embarrassing, it was, but I saved a lot of awkwardness for when they were going to tell me thanks but no thanks.