Hi My name is Evans Wanjau from Nairobi Kenya.
I had a similar problem with a samsung galxy s6. My solution worked 100%, I didnt have a pc and my phone didn't detect an OTG cable. Here's what I did...
1. Once I got the samsung account login there's an option for using the emergency dialer.
2. I clicked on the emergency dialer and called 911 (999 and 112 also worked).
3. While it's still on call the dialer provided call options (loud speaker, bluetooth, hold etc) represented by icons.
4. Now here's what I didn't know, there's another menu once you swipe left (This is samsung s6). On this menu there's messaging, email, web etc.
5. I then clicked on web which then directed me to chrome. Chrome first required me to sign in to the phone's google account to access it.
6. After that was done, I had access to the browser, so far so good. Next I download rootninja's app that enables you to access your phone's settings once you launch it 'samsung bypass google verify apk'. You can get it here
7. Upon downloading it I launched it from chrome and it directly took me to my settings.
8. I went to backup and reset and clicked factory reset, It required me to sign in to my samsung account. Once I clicked delete all, it kept looping me back to sign in.
9. I took a step back and chose the reset settings.
10.The phone restarted as a new phone and didn't ask for my samsung account.
- If this works for you dont forget to thumbs up and follow me on twitter @evanswanjau