Old mutual bad services

My sister had a policy with old mutual, through out of the years she made several enquiries to ensure her policies are up to date. She was ensured everything is on track. When she had to submit a claim, suddenly the date of birth and the id of the deceased is different, yet she went previously back to them to fix it, only now with the claim are they refusing to pay her out the amount that is stipulated in her policy documents. These companies are out to rob us of our hard earned cash.