Unable to receive my tax certificate of my annuity from Momentum

I have tried (unsuccessfully) to receive my tax certificate from Momentum, despite phoning them on 3 occasions. At the end of each call I was promised that my tax certificate would be sent to me via email shortly. Sadly the promised tax certificates never materialized. I find this conduct highly unprofessional and am now at my wit's end to understand how I can possibly obtain my tax certificate from Momentum.