Some of my verifiers refuse to give me their number (busy, aren't comfortable being on the line with med schools, one actually doesn't have a phone), and therefore I have to resort to providing an email only. Will it look suspicious providing emails for verifiers but no number?
And also, does the verifier have to be a person of authority? At the hospital I volunteered at I didn't know the volunteer director, so I put a fellow volunteer who can account for my hours.