Just to let you know exactly what her email said:
All post are funded to support the needs of the service, and we need to provide cover up till 4pm each day for client care. We need to be fair and equitable to all staff within admin and clerical, and therefore can i ask you to please look again at your availability. cover will have to be undertaken for core hours which are 10am-4pm and if this is not met through general discussion, we may have to involve HR to determine the outcome. I await your response.
this is what manager sent me, after i told her i can only work to 3pm.
http://www.theanswerb.../Question1100097.html