After retuning True like Bayo suggested, does this solve the problem?
I think generally, you will not want to have that else statement that response with something similar to "Wrong message
format.rct_notify.app.py!" as this will produce that and the message will still be propagated to the next app.
You're better of adding the "rapidsms.contrib.default" app to your INSTALLED_APPS settings and setting DEFAULT_RESPONSE in your settings file to the response you want to generate if the message format is wrong (i.e. it neither starts with "va" or "rct".
HTH