For starters, backup all of your data. Google Photos is good for photos, otherwise an SD card works too. Pull the SD card out and do a factory reset. After you get it running again, go change all of your passwords (I recommend a password manager like Last Pass for this) and enable 2 factor authentication wherever possible. Also make sure to correct your bank's contact number and do not turn on the ability to install apps from known sources.
This should remove any hacking localized to your phone/accounts. It's possible the phone itself wasn't hacked, but something like your Google account. If they hacked into that, they could change that contact number remotely and it would sync back onto your phone. That's why I also said to change the passwords.
It's also pretty hard to hack into Android. With strong passwords, and not visiting sketchy sites or downloading apps from random websites, you should be fairly safe. Getting hacked is largely because of something the victim did. I.e. Installing pirated apps that were modified to include malicious software. I'm not saying you did anything specific like that, only that you should be mindful of what you're doing.
05-02-2018 12:49 PM