Absolutely poor judgment and assistance

We booked return flights to George from Oliver Thambo. 29 Oct - 2 Nov FU8LVN, which I had to cancel on the 30th October, a day before because my partner's father had a heart attack and was admitted in hospital. I have asked if we could please use the tickets for another day later this year. I received an email today stated I must cancel 24 hrs before the flight. Surely a heart attack doesn't have a specific time or place. I am sure flysafair can assist better in this matter.