I had an interview and a computer test on excel. I couldn't do pivot table at the test. I wrote an email to the director who interviewed that I can learn excel in no time. She still gave me the opportunity for the second interview. I found a job before the second interview so I didn't go.
People understand that you can learn excel quickly so it's not a problem if you don't know vlookup. It's just some excel functions. If they insist they need someone who knows vlookup or pivot table, you can move on and find a better job.
By the way, found out how to use vlookup, hlookup and pivot table before your next interview.
Good luck
