Accepted an interview invitation and then the school rescheduled?

[rnicole]

Hi all!

I just received an email that I was being extended an interview that was about 3 weeks out from the current date.

I responded around 4 hours after I received the email to accept the interview, but I received an email a couple hours later that they were going to have to reschedule and that “they would email me when another date opens up”. 
Has this happened to anyone else??

Should I be worried? Or do they send out more interview invites than spots that they have open for the day because they know that some people may decline? 

Thanks!