I work via an agency for Amazon (night shift 6.30pm - 5.00am Sunday -Wednesday). We have been told we need to do compulsory overtime during the Christmas season, I can't remember whether or not I have signed for this in my contract or not.

On last nights shift they sprung it on me that I will need to do an overtime shift this Friday, my wife is out on a Christmas do that night so I need to look after our small children & next week we are at a wedding 200 miles away and the hotel has been booked for weeks.

If I can't do these shifts are they allowed to sack me?

Hi yeeeah if you could go ahead and come on in on Saturday that would be greeeeaat.

just talk to your manager and tell them you didn't know it was mandatory and you already had plans booked for a while

no

how ?