The problem is: regardless of what you work with, there will be restraints on what you can do. It is part of the job. If you don't like the restraints you shouldn't work on that field. Nobody promised absolute freedom.
Well, you're free to work where you want... But, the law is real clear on business obligations - you take the money and even a verbal agreement is a contract. You have a duty at that point to give the customer what they were expecting to the best of your ability at that point.