How to Get a Code to Sign Up for an Online Account When I Have to Use a Computer Located Not at Home, so Can't get the call with the Code?

I need to sign up for an online account, however I have no computer at my home.  I have access to a computer either at the library or at work, but when I'm at either of those computers I'm not at home, so it's impossible to answer the phone call from AT&T that provides a code that's required for me to input online to create an account.  This is a real catch-22!  There must be another way to get the code, however I cannot find any information on the AT&T website regarding how to do this.  Please help!  I need to sign up for an online account so I can receive and pay my bills electronically as they never arrive via the USPS.