If your signature was notarized...there is no room to dispute that, unless you're saying it was forged or signed under duress! I assume, that you want to 'get out' of whatever obligations you have signed for. In that case, you will need to speak to an attorney. (I'm a notary, NOT a lawyer)
From my understanding, a notarized signature is only authenticating that the person who signed a document is actually that person, not an impostor (fraudulent signature).
The contents of the document you signed might be the binding agreement you want to get out of. Nothing to do with the notarization. As stated above, you've got to see a lawyer to get out of a contract (if they can find a loophole).