Freelancer — reversal money from my account

I got one client on freelancer and i work with them but he offers me to return 50% of the money from that project.

I return to that client but after some time freelancer.com make the reversal of that amount to the client means client get my work and his full amount.

I don't know what happens to me.
And freelancer team blam on me.

I want to block freelancer.com forever so feature freelancer will not have this issue.