Change of seats after I paid for specific seats

When I booked my flights I paid for specific seats on the flight from Istanbul to Los Angeles. The seats I selected was in a 2 seat row. I got different seats in a 3 row seat. This means that my wife had to sit in the middle, next to another passenger. I specifically selected and paid for the seats as there was only 2 seats in that row to make sure that we had the row for ourselves.

The costs for the seats were R 3200. I need to get my money back.

This is the absolute worst experience flying with Turkish airlines. From booking in at Cape Town airport, flight delays, baggage lost, baggage damage to not getting the seats I paid for.