1. Tell them you're going to tell the accelerator about the IP dispute 2. Just tell the accelerator that you believe they're infringing your IP. 3. In future,

1. Tell them you're going to tell the accelerator about the IP dispute 2. Just tell the accelerator that you believe they're infringing your IP. 3. In future, get some form of paperwork signed early - I've used http://www.seedcamp.com/2011/09/seedhack-founders-collaboration-agreement.html http://www.seedcamp.com/2011/09/seedhack-founders-collaborat... in the past.