Monthly Funds Not Paid

My mum has been recieving my dad's pension from Sanlam since his passing for over a year now on a monthly basis. However last month upon review of her bank statement we see that the money was not deposited. I have called Sanlam and keep getting the run around. They keep saying they have no records when I give them both ID numbers and when I say can I speak to someone senior they play dumb. This is the worse insurance company I have come across. All I want is to retrieve the money owed which my dad left for his wife. Please if you are looking for any form of cover avoid Sanlam, there is definitely better out there.