Other Middle East and Africa Frequent Flyer Programs - Quick help with SAA question?

Hey there, I'm flying KLM ticket but there is an SAA segment:
CPT-JNB on SA, economy booked in "S" class--19:50 on 18th March--
then JNB-AMS-IAD on KLM.
A few questions:
I called SAA reservations and it seemed quite pathetic: I was told "There is no seat map" for the flight, so I can't book a seat ahead, and also when I tried to give my Frequent Flyer number (*A Gold), he said it wouldn't take.... ugh. Then I asked where the SAA city ticket office is in CPT, since I'm right in town, and was told, "I think there's one in Johannesburg."
1) Should I call back, or was he correct on all 3 of those? Don't know whether trust it. If it were Delta (the airline I know/loathe best) I'd keep calling back....since phone agent are often useless. :D
2) How is the CPT domestic lounge? I'm Star Alliance Gold. If I get there early, is it decent? Food, drinks, newspapers, etc?
3) If I check a bag, am I in trouble? A friend just flew this exact itinerary last week, and his bag was lost by SAA..... is that a rare occurrence? I actually have good image of SAA so am currently puzzled by all of these things.
Thanks for any info/advice!

You can insert your FF number when you check in online and select a seat (online checkin opens 24hrs before takeoff). CPT Lounge is very good, I haven't used the Gold section since they redone the lounge, but was in Plat section last week and selection was very good.

Lost luggage is rare and unlikely, guess it can happen anywhere, but I wouldn't be particularly worried. Just ensure no valuables are checked whatsoever.

Have you tried using the "manage my booking" @ https://www.flysaa.com/za/en/searchpnr.secured ??

Called back to be sure, and yes there is no seatmap. And FFN couldn't be input. And she already told me I won't be able to check in online, as it's a KLM-issued ticket.
Lovely!