The main problem for receptionists is that they deal with ill people, or the relatives of ill people all the time.
This calls for great reserves of tact, patience, humanity, sympathy, and empathy - most if not all of which a lot of receptionists either never had, or if they did, it has been worn down by the nature of the job they do.
Therefore, when you ring up for the first time, you are the nth person that day who is poorly, short-tempered, worried, frustrated, or just generally cheesed off.
This makes interaction difficutl.
An ideal solution would be to ask at the interview if the interviewee has really thought in depth about the type of calls they will get all day every day, and if they are up to being as polite and patient as they can from the first to the last.
99% - if they are honest - do not have those skills, and should not get the job - but of course, they do.