Unprofessional Service

Booked my car for a service for Tuesday. Nothing was wrong with my car, I would know. When I went to collect my car, they told me that my car's waterpump was leaking. It was perfectly fine before the service. On my way back to work, my car started to overheat, the heat gauge was over 90. Took my car back this morning, and the Service Manager told me that it was murphy's law that my waterpump & thermostat is broken! How unprofessional is that, and not only the waterpump is completely broken, but the thermostat as well. They wanted to charge me R5800.00 to fix the waterpump and thermostat. I honestly think that because i have a service plan on my vehicle, they did not really care about the service and did not really fully attend to the service. I took my car to them, in perfectly working condition, and received my car back broken! I know my consumer and customer rights, and what happened here is CMH's fault!