Hi.I have a roaming problem that is started from symbian Anna OS and continue windows phone 8 on nokia phones.my meaning this problem there is not on symbian before Anna OS.I live in iran and MCI operator(IR-MCI) customer. MCI sim customers can inner roaming on Villager gsm network(IR 70 or 43270). when roaming on villager gsm I can send and receive sms but I can not any dial an receive call contact and show Network busy error for me.now I have a lumia 520 and that has this problem. until ere this, I had nokia C6-01 and N8. when update them to symbian Anna and belle this problem appear my phones on roaming. please help us and solve this problem.