It is worth being aware that contracts are either express or implied. An express contract is one where the terms of which are stated in words. An implied contract is one where the existence and terms of the contract are manifested by conduct of the involved parties. A contractual agreement can be oral and in many US states (for example California) and Countries (UK etc) it is enforceable - especially if there are witnesses or proof of joint activities etc. Your best bet to get out of the situation is follow Tzunamiton's good advice and find someone you both trust and that you can both agree as an impartial adjudicator. Then discuss with the adjudicator to either wind the company up or get a written termination agreement that you are both willing to sign. If you want to pursue the idea then the termination agreement between you and your former partner must set out the payment terms and limit or sign away any future claims against the idea/ip. hope this helps.