Counter-question: Was the Pro-finder already enabled to do this with a programming text message?
This has to be done first. Without the appropriate programming, it does what it is supposed to do – ignore ‘foreign’ commands.
If programming was done from the app and you didn’t receive a status report afterwards, the SIM card was probably already in the device before it was activated by the provider. In that case, the Pro-finder must be disconnected from the power supply for 5 seconds in order for the SIM card to log in again. Then the power supply should be restored. After about a minute, you should be able to get a response.