Uncaring attitude from Old Mutual. No requested IT3 a certificate

My 97 year old father has an annuity with old Mutual that pays a small amount each month. I am trying to sort out his tax affairs and I need an IT3(a) from 2019 to finalise his taxes. For 2 weeks I've been sent from pillar to post by Customer service at Old Mutual, sill no tax certificate. I tried to escalate my problem but after holding on the phone for almost 30 minutes, I was told that superiors are in a meeting. I left my number to be called back, it's been 5 days, and I'm still waiting.