Assume they have sold me their software. I am using this app that contains GPL licensed code. AFAIK, they can't take back this software I've bought from them, a

Assume they have sold me their software. I am using this app that contains GPL licensed code. AFAIK, they can't take back this software I've bought from them, and due to the GPL, they are obliged to provide the source code for the entire app to me if I want it. Whether they stop infringing on any further sales of the software is of no consequence to me and to the software they already sold me. IANAL.