If you feel that your phone has been hacked, then here are some of the necessary steps that you need to take before any serious damage occurs.
Change all your passwords immediately.
Remove or uninstall any suspicious applications
Run a virus scan
The methods stated above are some of the basic ways to remove any threats that may be present on your device. However, depending on the intensity of the data breach, you might also need to restore your device to factory settings to nullify the threat.