^ This I know you edited your post saying you would't, but do NOT do anything to their codebase/website etc. Don't even remotely entertain the idea. Similarly

^ This I know you edited your post saying you would't, but do NOT do anything to their codebase/website etc. Don't even remotely entertain the idea. Similarly, don't spout anything libellous incase they end up going on the offensive. Best thing you could do is pick up the phone and actually call them and give them a chance to respond (they're humans just like you) and if they dodge your calls, go for a debt collection service.