Can i sue someone who owes me money from a business venture and never paid me. we have a contract? -

With much regret you can sue just about anyone for just about anything. If you win or not that is another question.

If you have a contract, can prove that they violated the terms of the contract, and, can show that you were materially harmed by their breech of contract, you probably can win your suit.However, that just gets you a judgment entered against them. Collecting is yet another matter. You first must ask yourself if the amount of money is worth the cost of pursuing it. If it is, then go for it. If it is less than the small claims limits, you can save a lot of time and money by going that route, but, you have the disadvantage of it potentially being even harder to collect.