How to remove GPS spoofing from your device
Disable the spoofer first, then remove it, then verify your real GPS works.
Settings → System → Developer Options → Select mock location app → 'No app'. The phone now uses real GPS again.
Settings → Apps → find Fake GPS / Location Spoofer / similar → Uninstall. Reboot. If you can't uninstall, it may be set as a Device Admin: Settings → Security → Device admin apps → revoke first.
Settings → General → VPN & Device Management → remove any unknown profile. If your iPhone is jailbroken (it shouldn't be unless you did it intentionally), back up data and restore via Finder/iTunes to factory iOS.
Open Maps and tap the location dot. It should pinpoint where you actually are within a few metres. If it's still wrong, restart the phone and try outdoors with a clear sky view.