While I'm not sure that's high if it includes the parts replacement, I feel strongly they should have told you what it would cost before they serviced it. And at that time they would have told you what it entailed.
Odds are if they had done that you would have considered it reasonable, but when they don't it does make one wonder, and rightly so.
Not familiar with the machine in question, but if it's rare to have it serviced, it might be worth it. They should offer a 90-day warranty on service and if they don't, I'd find another company to service it in future. (I do realize that isn't always possible - so any future service should include the words "Please call me with an estimate before you start working on it")
IMHO