Refund isn?t something I do and it?s not mentioned as an option. According to my recollection it has happened to me twice that I was asked....
First time ( many many years ago), I lied and said that the money had already left the building so not possible.....
Second time, was a few months again where the guy booked for 2hours but only stayed 1H so I gave him som change back.
I have worked since 2009 so among the thousands I have seen only these can I vaguely remember.
You did right and I would have done the same thing but try different tactics to avoid the situation (conversation, a drink of water, long bj, long hand job, longer foreplay, massage)
Good luck...