I want to end my Xbox Live subcription.

I have one month Xbox Live subcription on my Xbox 360 and my friend's microsoft account is on it and he doesn't remember his password and he can't return his password back. Is there any way I can take off my credit card off my Xbox so I don't have to pay
for nothing. When I have tried to return my friend's mailpassword on Gmail it says that there is no gmail of my friend's. How can I end my subcription??

:)