Appalling Service from Old Mutual

I have attempted to phone Old Mutual nineteen times this week, following the death of my father. I need them to transfer his annuity payments to my mother. In addition to the phone calls (each of which has cut off after 15 minutes of waiting, including to the Complaints Department), I have sent two emails and joined online chat three times. I have never received such poor service from any financial institution and is causing my mother severe anxiety.