Kulula is taking me for a ride!!!

I made a booking for 4 people on 26 September 2019 for this coming Thursday 10:00am. Unfortunately one of the four can no longer honor that commitment. Consequently, I have found another person to take up the vacant seat, however I am told by both customer services and feedback directorate that name changes is not allowed as per company policy. Not only am I perplexed by this said absurd policy but also cannot stand the thought of paying another return ticket for the new person while there’s an empty seat that I had paid for and cannot be taken up another person who’s now coming with me. I honestly do not see any prejudice caused to Kulula by this proposed name change. To this end, other than telling me about this said policy, no one has justified the clause in question as to how will the name change prejudice Kulula.