I work part time at a restaurant along with studying for a degree in the week. i’ve very explicitly told my manager my limit is 20 hours a week, and most the time i’ve done my 20 hours before the weekend comes round. at least twice a week every week she will message me asking if i can come in to ‘cover’ or ‘help out’ for someone who’s called in sick. i really don’t want to but the way it’s phrased is an expectation for me to come in. it’s really not my fault if someone calls in sick and when i say no i get met with something like, ‘we could really use the help from you, others have helped out before’ or ‘we like people who are dependable in this company’. it’s getting pretty tiring. if one person calling in sick messes up service for the entire restaurant, why should i have to work over my stated hours for the week? it’s happened twice in the last three days, both times on days i’ve explicitly said i’m unavailable to work on. forgot to add – if i don’t reply within half an hour i’m met with constant phone calls from the restaurant which i also ignore.