I've lost my return package. What should I do?

Please proceed to the closest post office and purchase a prepaid package called "LetterPack 510", and send back all the rental items to the address below:

6F Toei Bldg.,
6-1-8 Motomachi-dori, Chuo-ku, Kobe,
Hyogo, 650-0022, JAPAN
eConnect Japan Inc.