My internet doesn’t want to work

I have tried to use the mobile app every time I try to login in it it doesn’t want me to login. Keep on saying return again and re-login and also I can access my account. I checked the bottom of the Internet device to get the password in the bottom then when I try to connect the Internet, it keeps on saying no Internet so I login I paid my account and I tried to use it again. It keeps on saying the same thing over and over and I don’t even have balance in my account  why my Internet is not working