Cs-Coding Review

First, this developer refused to enter into Statement of Work agreement where all our requirements are listed and instead insisted that we go by a word doc list which he inaccurately prepared off of the list of our requirements. I agreed and let it go.
We came to a price agreement for the project separating into 3 milestones.
When first milestone was almost complete, he suddenly changed prices of other milestones saying that he has other work/projects/limited time and saying that his price for other add-ons will be x3 agreed price.
I don't know if he was planning to use tactic from before but we go into disagreement and have a argument and that we will not continue on other milestone after this milestone is done. After this he stops making all changes in the first milestone even after offering him extra price to complete the first milestone. So he left me with incomplete add-on while I prepaid first milestone in full and even offering him extra to complete the first milestone. So I just told him to deliver the ZIP file of incomplete first milestone and we stop working with each other but even that he refused to deliver zip file telling me to copy the changes myself but later agreed to change.
On top of this, he is rude and unpleasant to work with. I don't understand how this developer has five star rating so I was equally surprised to see this.