OIM1 error - can not ring a specific landline number from my mobile
I am having a problem ringing my parents landline from my mobile. I can use their landline to ring my mobile and I don’t have any problems. I can ring other landlines. I have spoken to Optus and they hate hopeless. They put me through to the land line team who the transferee me to the mobile team. 30 minutes on hold and no resolution. Does anyone else have this issue?