Now I have a client, and I make all he wants with the deadline and makes all edits. but suddenly He gave a very bad feedback and he refused to change it.
How I can make the dispute for although the contract ended?
Mena, normally feedback can not be disputed. In those very rare instances where it may be able to be it must violate UW's TOS (terms of service.)
If you'd be Top Rated, feedback removal would be an option. In your personal case there's the option of posting a response to the feedback which you've already done.
The Client could contact you for you to allow them to change their feedback. Even if that would occur they could change it to be poorer than what they originally shared.
Try not to be overly concerned with it. Just move on from here. Select projects you're confident that you can successfully complete and do your best with each one of them.