plugin registration failed

Hi, I bought the plugin a few months ago. I installed it on a site. I think I deleted this site. The problem is that I cannot install any more the plugin on another site . Can you check on which site is registered the contentomatic plugin ? or deactivate it , so I can install it on a new site. I have the same problem with Newsomatic plugin I hope you can help me with this issues   best regards   Olivier