Uppruna tekstur - Enskt - Vodafone contract

My name is XXX. I received a contract Vodafone in July 2009. My sponsor is Army military and is going to be retiring the 31st of August 2009. I do not live at the address #53 Dozeystrasse. I will have to return to the United States. What information do I need to provide to the comapny in order to discontinue this contract since I will no longer be in Germany. My Vodafone number is XXX. Thank You