Thanks for using the forums, the behavior described is expected when connecting your VPN of dropping the internet connection for a moment and then the internet connection being restored after the VPN connects. If you believe you tech has been hacked you can try using iVerify to see if it detects anything malicious or out of the ordinary.
If you want to be safe it is never a bad idea to perform a factory reset by using the following procedure after baking up any important data stored on the phone.
1. Open Settings > General
2. Now tap Reset
3. Select “Erase All Content and Settings“
4. Tap “Erase iPhone” on the prompt
5. Enter your Apple ID password then tap “Erase” to begin the factory reset process