Write it off. One thing I probably would do is send a friendly e-mail to the investors, explaining the situation. Keep it short, a few sentences max. Given the situation, offer they pay you a reasonable fee for the problem to go away. Do you have any evidence supporting your claim?
The fact that there was no formal contract does not mean he legally owns your IP. E-mails can be valid contracts. Did they rebuild the software or continue working from what you build?
Problems like these can be major deterrents for future investors/acquirers.
The fact that there was no formal contract does not mean he legally owns your IP. E-mails can be valid contracts. Did they rebuild the software or continue working from what you build?
Problems like these can be major deterrents for future investors/acquirers.