I Can’t close my microsoft account, please help.

I have two windows live ID (microsoft account) and i need to close one. My university provide me an account that i´m using with my windows phone (*** Email address is removed for privacy ***) but i have an older account (*** Email address is removed for privacy ***) which i activate as a passport account (long time ago) just to be able to use it with msn messenger. I will not use this microsoft account more and i want to close it totally.

I have try to close it using the "close account" button in the Microsoft Account overview, but it give me the famous message "You need to cancel any paid services or Microsoft Points account associated with your Microsoft account". When i first set up my Lumia, i use this account in order to test the phone, and try some app; i have read and understand that there is must be some service activated that don´t let me close the account, but i don't know what is it or how i can close it.