Problem with more than one device

Hello, I just paid for a week plan. I have already connect my laptop to this wifi and it's working nicely. However, when I tried to connect my phone the internet was literally frozen in my laptop and working in my phone. Looks like it can only work in one device at once, although I read that I can connect 20 devices, BUT with only one password which means I am using the same account and password for both devices because that's the only account that I have to pay. So, how can I connect more than one device with the same account?

THanks