In all seriousness, I would give her a call back and ask her to 'get into specifics', because it's totally unacceptable that they're not giving you a reason for letting you go. If you go to get another job, they may well ask you why you were let go from your previous job, and saying they wouldn't tell you is going to look bad. Besides, I am sure they're legally required to give you a reason. Honestly, that's atrocious stuff right before christmas. You should definitely give them a call back and find out why, because they have no right to fob you off like that.