Am I bound by an LLC agreement that I was not shown and then refused to sign when asked to?

I was hired as an employee in 2005 of a private equity fund. As part of my compensation package I was given a share of the fund's profits and also agreed to invest money in the fund. In 2009 as I was thinking of leaving, the firm's owners confronted me with an LLC agreement governing the partnership that managed the fund and told me to sign it. It contained many restrictive covenants and so I refused and within days left the firm. They now both refuse to pay me my share of the profits earned between 2005-9 (which were vested) as well as the fair market value of the money I invested in the fund on the grounds that I am bound by the LLC agreement which was drafted in a way that the firm's owners can strip anyone of their profit share and investment amounts at essentially their discretion. They concede that I did not sign the agreement.