It does sound like two different issues, but in the same basic location in your home.
They did send a plumber out a second time, to work on something that you installed. Right?
Fifteen minutes? If they are like most contractors, they have to charge travel time. If they say they don't, they really are. It's built into the price most times.
Then you also have the minumum charge that many places charge for, which can vary a bit, but there is no such thing as a 1/4 hour show up fee that gets any work done. That fee is just to write up a quote.
The other day, I dropped off a part in Seattle for a job my son was working on. In the evening it would have been much quicker, but during the rush hour drive time, it was 1.5 hours, and I spent no time on the job.
Take all those 1.5 hours, with no time on the job, and if you weren't charging for it, how would you buy gas even?
But the pump is working, and the back up pump too, right?
It's all good.
And no, I wasn't able to charge for my actual time for dropping off the part, it was more like a money loser, but it kept the job moving.
I'm always amazed that UPS will deliver to someones door step for less then $15
But then when you look at the trucks, they're dropping stuff off on every street as they drive by. Those $15 charges start to really add up.