What's worked great for me with Amerigas when my tank got low is e-mail at
www.amerigas.com, located in King of Prussia, Pennsylvania. I e-mail them: "Hey Amerigas-Laconia NH, my tank is down to 20% so's I was wondering if you can do a fill up." ..... and e-mail seems to work very smooth .... two days later the tank got filled, and the next day after my one and only e-mail I got a courtesy e-mail reply, acknowledging my e-mail.
Best way to communicate with King Amerigas is by e-mail cause they probably don't particularly, really want to talk to you, and prefer e-mail.