facetime keeps failing

I am using an iphone 4s... IOS 6 .. I Do not want to update to ios 7 due to how it looks . My friend is updated and also has the same problem on her 5. Anyways whenever i call someone and they answer it says connecting ... then facetime failed. If they call me then it says connecting... and then facetime ended automatically. please i need this answer urgent to see my far away aunt whom has a dying husband and i need to keep up on how their doing without going over there