My experience is that when making a reservation through the SAA website with a non-SA credit card the side informs you that the ticket can not be iussued with the CC details provided. The reservation however is valid and I normally then go and pick-up the ticket at the airport. This is for C-class tickets at least (never experienced SAA on Y, but from what I have seen the difference is marginal in any case...)

On pricing; C fares normally show J or Z class and are cheaper when being booked through the website than when bought through an agent.

And finally, with their level of absense of service and customer-care at all levels I avoid SAA whenever possible.

Cheers,
JNBHEL