How do you handle a client who tries to renegotiate the price after the work is done?

[Btaliat]

There is no need to panic. You only need to refer them back to the contract that you both signed. They need to stick to the money that is agreed on. It is not professional to be agreeing to what the clients propose after the work has been done. However it doesn't mean it doesn't happen. Freelancers are to be solid enough not to be taken for granted by the clients. What do you have to say about this?