[Sir_Dispensalot]

aye - stick a quick advert up for a saturday job - they fill really quickly with students and sixth formers wanting some extra dosh! Start advertising BEFORE your leaver goes!

In the short term - how difficult is it to run the branch without the dispenser on the saturday? Is there a counter assistant there too? Is it a quiet saturday - do you cover the saturdays - is it possible to run it solo for a few weeks?

Are you part of a chain? Could you 'borrow' someone from another branch? Any relief floaters available?

Worst case scenario - use their contracts against them!
Ask your head office / human resource dept for copies of their contracts and go over them carefully with respect to the working hours, times and any clauses such as 'from time to time we may ask you to work a different shift pattern or alter your hours to fit in with the needs of the working environment' or words to that effect. Then ask them nicely again after referring to their contracts (preferably with the backing of your area manager - present with you if possible). If they still refuse without good reason then do em on a disciplinary. If they're the 'entrenched' kind they then will threaten to leave at the same time. Point out that although you value their contribution to the team greatly if they were to leave it would only have a very short-term impact on the branch and future employers may take a dim view of this on their references.

Hopefully then they will back down and having realised they can't win the pissing competition they'll get on with what you need them to do.