App Store retrieval

Hi Guys,

Any regular App developers out there ?

Does anyone know if there is a way to retrieve an APP which a developer has created and setup for a client, the developer then goes AWOL leaving the client high and dry with no access to anything , no Andriod market logins, no Itunes logins .

Obviously starting from scratch isnt an option if the app is popular as all users would need to purchase again.