STD Bank Not Easy To Contact

My father has a policy with Standard Bank, he is old, not using internet and sickly. He asked me to obtain documents for his funeral policy, as he needs to get his documents in order. He signed Special Power Of Attorney giving me powers to communicate with the bank, obtain statements or any other information in this regard. I called the Standard bank line since 5 February 2021, to date, no response. On their website, they refer queries to an email, i have been sending emails to them since February 2021 to date, but i always get the below message....

Delivery has failed to these recipients or groups: *** Your message can't be delivered because delivery to this address is restricted.

My father cannot go to the Branch, and hence he asked me to do this for him. Is there a working number we can call, and get response. I was on the line for 34 hours 17 minutes 22 seconds since February 2021 (As recorded on my telephone bill), and on all occassions, i couldnt get a response, i was just holding.

Kindly furnish me with the procedure to address this issue.