Price-gouging inflexible seat booking policy

I just booked a premium seat on the Pretoria/Cape Town route. The online system didn't offer me a choice of seats and assigned a seat next to the toilet. When I phoned 10 minutes after making the booking, the customer "service" consultant told me I'd have to pay 20% to change the assigned seat. That's over R300. Nope. Not happening. Very poor price gouging policy.