Did Quark have legal grounds to terminate the Ferengi contract in Body Parts?

In Body Parts (S04E24) Brunt pays for Quark's body parts vis a vis a contract that Quark accepts/signs. However the whole premise of Quark dying was a setup to get him to accept the contract by faking a terminal illness. Everybody says "a contract is a contract is a contract" and while this is true, wouldn't a scenario whereby a party is tricked into accepting a contract under such circumstances, probably happened in Ferengi society and they would have rules and laws against that sort of thing? Given Ferengi's cunning nature I would think laws like that would exist in their society to prevent each other from getting completely screwed over. Just some thoughts. I just feel that Quark had legal grounds to challenge the validity of the contract and get it nullified.

What do you all think?