Feedback system

Can someone advise , recently I worked on the small project on 1 time basis . the milestone was approved 3 weeks ago and got paid . But as usual , clients took a piss and paid me less .I had no other option to walk away with less payment .

Now , if i end the contract , which is 3 weeks post completion and leave a honest feedback . Can that client still leave a feedback because i dont want to ruin my JSS score