Date Auto corection from site Costing us R8800 unexceptable

Three Flights booked back from OR Thambo for 4 Feb. Selected option was 4 Feb! Tickets printed and payed on night before return it read 4 March!! Total fee to change tickets R7545 Forth ticket also bought online via office in JHB ( No connection between Buyers) OR Thambo to PE ticket Price for change R1250 . No explenatin from mango! 1.Didnt Answer their Phones 2. Website kept dropping hence the *******ion on ticket dates. 3. no clear contact line or person to talk to!!! Need this Cleared up! Odds of two different people booking 08:00 flights from 2 different parts of the country making the same mistake.... impossible