Issues with tax free savings payout

Good day

I am struggling with Old mutual to payout my son's tax free savings. I opened the savings in his name to save for emergencies. He is 5 years old. Previously when i requested withdrawal, they asked for his birth certificate, my id and my banking details within days is paid out into my bank account.

Now from the 6th of November i requested a withdrawal but they still not paid out. They requested the documents as always, i send it through numerous times and now they keep asking for bankkng details in my son's name, we dont have that because he is a minor and previously they did pay out into my account, the is not very good customer service at all!