Advocate NOC

I had submitted a application in the civil court personally that i want to withdraw my advocate's vakalatnama as I have no faith in him due to his connection with opposite party. Now i want to appoint new advocate for my civil suit case but other advocates demand Noc from that advocate. But that advocate is adamant and demanding huge money for giving Noc. Infact I had paid his fees cash. Now i want to know what legal remedy available to remove that advocate from my case and to satisfy new advocate for appoint him without Noc.