Mango Payment for Extras - No Service on Flight

I paid an additional R330-00 to reserve seats for the 3 passengers that flew from Joburg to Durban on 3 April 2015 and returned on 7 April 2015.<br> <br> Upon online check-in for the Durban - Joburg flight, I discovered that the seats I paid to reserve (5D, E, F) were allocated to someone else and my passengers were spread in different rows although travelling together. Mango agents at King Shaka were totally clueless and rude at first, not knowing how to resolve this issue.<br> <br> I paid for a service that was not provided by Mango. That in itself is ***** as they took my money and refused to provide the specific service that was paid for. I want to know who changed my seats as I have written confirmation from Mango that the specific seats were reserved for me.<br> <br> Mango will not respond to my emailed complaint.