Wants payment without agreement

I called Mr Naude because I required assistance with a court case. He did not have a consultation with me or discuss his fee with me. He also did not indicate how he intended to handle the court case. I am not guilty of the charges, I told the attorney that, and I gave him an affidavit from a witness. He made no attempt to have the charges withdrawn. When I called him to enquire about his fee and his intentions regarding the case, he informed me that he wanted to withdraw from the case. A few weeks later, he informed me in writing and sent me a bill. As we did not have an agreement regarding his fee, I paid him what I thought was fair. He refused to accept my offer, and issued summons for R8,140.