[radio4fan]

Or looking at it another way, OP has trained the client to continue to act this way by rewarding his undesirable behaviour.

Its like giving a dog a biscuit every time it pisses on the rug.

Still, I feel that the fair solution to both parties is to explain to the client why the important and urgent items are going to take much longer than he thinks.

OP could look on this gig as an opportunity to train himself in managing clients, and therefore walk away with some benefit.