Absa life insurance policy not paid out.

My father died on the 5th August 2019. We went to Absa Oudtshoorn branch to close my fathers bank account. The lady at the info counter informed us not to close the account as there is a life insurance policy on the account in the amount of R 15 000 that in the event of his death will be paid out to my mother. My dad had used the Absa account for more than 10 years as his retirement pension was paid into that account. On the day of his death there was only R22.00 in his account and according to Absa, there needs to be at least R50.00 in the account for the policy to be paid to my mother. When my dad withdrew his pension, he left the R50.00 in the account as always, but the lady at the info counter informed us that due to bank charges there are no longer R50.00 in the account and therefore my mother are not entitled to the insurance of R 15 000. I have called absa regional office in George and they informed me that a representative of Absa will call me back. I have never heard from Absa again or their head office. I would like to know if there is anyone with a simular situation and if there is anything I can do to get Absa to pay the insurance policy to my mother.