Hi there! I understand you're having trouble opening the Guardio app on your Android 10 device and seeing a blank screen. Also, you mentioned the phone number you received might be a scam. Let's tackle both issues carefully.

First, about the app showing a blank screen: This can happen if the app's web session or cache becomes corrupted, especially on browsers or apps using WebKit rendering. To start, can you try these steps?

1. Force close the Guardio app completely.
- On your device, open the recent apps view (usually by swiping up or tapping a recent button).
- Swipe away or tap the close icon on the Guardio app to fully close it.

2. Clear the app cache and data:
- Go to Settings > Apps > Guardio.
- Tap Storage.
- Tap Clear Cache, then Clear Data.

3. Restart your phone to refresh everything.

4. Open the Guardio app again and see if the blank screen issue is resolved.

Now, regarding the phone number you mentioned as a scam: Guardio is aware that many scams involve fake tech support phone numbers trying to trick users into paying for unnecessary fixes or gaining remote access. If you ever see suspicious pop-ups or unsolicited calls claiming to be Guardio support, do not call or share any personal information. Guardio doesn't ask for payments via phone calls and blocks scam sites proactively2 7.

Could you please confirm if you downloaded the app officially from the Google Play Store? Also, have you tried the cache clearing steps before? If these initial steps don’t fix the blank screen, I can guide you through some advanced troubleshooting.

Let me know how it goes, and I’m here to help! Are you satisfied with this initial advice?