Game Center Help and questions

i cannot for the life of me figure it out...

i am trying to play fruit ninja in game center with a friend. i can connect to random people but not to my friend i sent them numerous request to become friends to no avail.... they sent me a request i got it and added them but we cannot connect. i can see her stats but we cannot connect.

i updated to 4.3.1 IOS but that didnt help. they are on an iphone and i am on an ipad2.

i also reset my network settings on the pad but it doesnt work ?

not sure how to make it work and wy would i be able to connect with randoms?

thanks for any help!!!!