I used my own modem

user_59xrdl Thank you so much for stopping in for help with this notice to return equipment. These notices are not always for modems. Does your current notice provide any details for the equipment? 
With some of our internet only plans we previously offered a Flex/Xumo 4k Streaming box free for as along you had Xfinity internet. There was not monthly rental fee but does need to be returned.