Help Gingerbread cannot call ICS ?

[Sum Sum]

I recently updated my Samsung Galaxy Note to Android 4.0.4. After that my husband cannot call me. My husband is also using Note but he has not upgraded to Android 4. When he calls me, he gets dial thru, but my phone does not ring. When he hangs up, I get the error MSG on my phone " process com.android.phone stopped unexpectedly." Then signal sign on the phone turns to no signal sign for a few seconds and then back on again. But I can still receive calls from some other people and I can call my husband. Samsung Hong Kong suggested me either to downgrade my Android or try to upgrade my husband's Android to solve the problem ! Would you have other suggestions to solve the problem ?