Not my account

Okkay so i had a friend who was living with us for a while he got an account with dish and moved out a couple months later. Before he left (out of the coutry) he told us he had cancelled the account and asked us to return the receivers whenever a box arrived in the from dish. We said it was fine and now a month later no boxes have arrived and dish is calling my number because he used it for the account and they are telling me he owes 361.00 plus a cacellation fee. Am i obligated to pay for his debt? Can i just call them back and tell them to send the box so i can send their receivers and have him deal with the problem when he comes back? I dont want to get in any trouble or make them think i want to keep their receivers and possibly have them coming to my house charging or something! Can they do that? What should i do?