<scratches head> I'm having a hard time keeping this all straight.
You've got at least 2 separate Internet connections, your wired landlines and your cellphone data plan.
You've got a browser in your phone, on your computer, and your mother's computer.
I see at least 5 separate tests to be performed, viewed the problematic post (full refresh every time
1) Your computer, landline connection.
2) Your computer, tethered to your cellphone connection.
3) Your phone's browser, on it's cellular connection
4) Your phone's browser, on your WiFi through your landline connection.
5) Your mother's computer, on it's landline connection.
Make sure you clear browser cache before changing connections on a device, otherwise an earlier successful test can mask a later unsuccessful test.