I would also just check to make sure there isn’t a list of emergency tradie contacts on your notice board. If there isn’t, then what ScotlandX says is absolutely right. If there is, you may have to put up a bit more of a fight (but you should still prevail).
However, if they say tradies are listed in your By-laws, or any other document, you can reasonably argue that you’re not expected to carry that with you.
Apply for mediation and if they still won’t pay up, make a claim at the Small Claims Court