Hello, my name is ***** ***** I will do my best to assist you. Give me a few minutes to look over your question and I will respond shortly.
If you look at the cable modem, there will be a sticker on it that has the SSID (which is the network you will choose to connect to) and there will be a Passphrase (which is the password ***** that connection). Try this and let me know if that doesn't work for you.
It may look like this.
Does the SSID on the sticker match the connection you are trying to connect to on your phone?
Yes, you'll have to connect to the CenturyLink router with a PC internet browser.
This link should have the instruction for changing the password.
If you can before you go, please rate my service with the stars at the top of the chat page. Let me know if there is anything else I can do for you.