Sounds like there was an error somewhere between your friend's phone and yours, and believe me that's a lot of space for an error to occur. Since you said you know the number have them do a battery pull on their phone, you do one on yours, turn everything back on and try it again. Make sure that you give a minimum of 5 minutes of downtime when you pull those batteries. If that doesn't help then your friend may need to reprogram their phone (Assuming that's where the problem lies, which it may or may not be.)
Make sure next time you post to include what make and model of phone you're using, and if possible the same for the other phone, details make all the difference for us to be able to help you.