Bullied by attorney

I recently settled on a Title VII lawsuit. THe contract between my attorney and I was 50% Contigency or hourly rate whichever was higher. Well since settlement came about I was under the assumption he was getting 50%, which verbally we discussed several times.I always told him throughout the settlement negotiations I needed to walk away with 20k so as long as he got at least 40k I would settle. He achieved getting the settlement to the amount I told him I wanted, Now that settlement has been received he has stated he is keeping all of the settlement and I still owe him 10k. Can he do this without have disclosing to me that the settlement he was urging me to sign was for less than what I owed him, so his hourly rate applied? I have never in three years seen a bill accrual or had any idea he was billing this to me, I never would have settled for less than I owed, not too mention Summary Judgment came all in my favor for Sexual Harassment and Battery, defamation and that my employer had every reason to know it was occurring. I am at a loss and need direction