Carol they also do the same thing with cameras and when they send then in for work they never tell you about it. When you inform then of this they sometimes say oh yet I meant to tell you about it. Then ask why is it costing more then the original quote and taking longer then quoted.
When I find unexpected finds like springs or parts missing I will ask about it and most say... "I bought it off ebay." I bet you get some that are rusty too and they kinda forgot to tell you that it just happened to take a dip in some form of water awhile ago, but they dried it out and it was working before they put it away the last time.