Extremely inflexible in emergency circumstances - disappointing

I was meant to be flying on the below flight (which I have subsequently have been informed has been delayed): Depart King Shaka (Durban) (DUR) O.R. Tambo (Jo'burg) (JNB) Tue, 03 May departing 15:00 arriving 16:05 On 26 April (seven days ago) I approached Mango (whom I was flying the departing leg with) and Kulula (the above return leg) and informed them of a family emergency which precluded me from travelling to Durban and I requested a credit Mango escalated the query on the same day and provided a credit also very quickly. Kulula however denied this request (with ample time to sell the seat) and showed complete inflexiblity in dealing with the emergency. Really disappointing as I spend several thousand Rand annually with Kulula and I would have thought they would've been more discerning in their customer relations. Regards Bryan Silke