I think we need @Benjamin_Nicholas to weigh in here....
Let me turn the tables on this question.... As a bottom who only hires providers who are tops, if they cum in the first 10 minutes and can't get it up again, should I only pay for 10%?
I don't think its fair to be upset with anyone who 'cums too fast' especially if it is a second time you are getting together with them. Cum happens.... be happy about that, not annoyed.
I will say, this is where this forum is SO helpful. If this was habitual behavior....cum quick and be done as a way to avoid further performance....then I think you could make a case that someone is trying to avoid providing services as promised.
If you cumming first is important or a bottom who can keep taking it if they cum first is what you want, talk about it before your session.... I LOVE asking tops if they can cum more than once in a session. Almost every time, they have been honest about it and I was never disappointed.
If you're that upset, discuss getting more time out of the next session or see if they will give you a discount....otherwise, let it go!