I don't think the design is going to work with the cord around the back of your neck. Unless it got printed all the way around, which makes it more difficult to produce, it wouldn't work at all in my book.
Agreed with mype4nut. But I do think the phone hanging round one's neck is cute. Especially since I used a corded rotary phone just like that one through most of my childhood. Other kids in the neighborhood would come over to play and wouldn't know how to use the phone.
I agree with changing the size of the phone, but the cord doesn't need to be printed al lthe way around, just enough so looking at this from the front you can't tell it doesn't go to the back.
About my design