FlySafair Business Class seat ****

I booked and paid for 5 business class return tickets to Zanzibar. On our return flight yesterday one of the seats was a normal seat. In a row of 3 people, the middle seat was supposed to be blocked but it was not. What is the use then of booking and paying for a business class seat? If I wanted a normal seat I would have booked and paid for it. My travel agent sent an email to FlySafair yesterday already, only to be told "the matter will be investigated". This is really pathetic. I feel that I have been ****med by FlySafair.