ex-husband owes me $ he never gave me even afer divorce papers were signed, still have joint account, can I take $ and close it?

My ex and I had a amicable divorce, that for the most part we just separated who got what. In the interest of getting the divorce finalized after he dragged his feet for 2 years, we did a cheap and quick divorce without lawyers. He ended up with all the big ticket items (dishwasher, stove, washer & dryer) and I also had financially contributed to many improvements to the house. In the 11th hour of getting the paperwork signed so it would be finalized by the end of 2012 I ended up signing papers that said we had met all financial and physical obligations to one another, even though he had not yet paid me the $. He PROMISED me he wasn't trying to take advantage of me, and would pay me the $. Despite my misgivings, I signed the paperwork to get it down, and of course haven't seen the money. We have a joint account still open that he still uses and hasn't been closed that I have not used in over 3 years. Can I take the money out and close it without his having legal recourse against me?