SWA changed their RR program about a year ago. Prior to the change, you were given award flights rather than points towards purchasing your flight. The awards had a number of restrictions, including black out dates and limited seats on each flight. But they were good for full flights, regardless of whether the retail value was $63 or $630.
If that's what you have, then the free flights from the credit card offer were supposed to be round trip. Log into your RR account and click on the "Where are my old Awards" to see them and to use them to book your flights. IIRC, those awards had an expiration date, so you might want to make sure that they are still good. I remember reading that you cannot pay to extend their expiration date, probably because SWA does not want to have those old Awards hanging around forever.