I notice mine does not like reloads too much, Kahrs are known to have tight chambers. Just shoot what works. Walmart typically has WWB (winchester white box) and the Remington bulk packs and either should work fine, its not premium ammo, but I would not consider it substandard either. If you wanna shoot the remanufactured stuff, buy a box and see if it works. Just make sure you lube it correctly.
According to the website, it should have come with two mags, but the standard may have been different at the time it was made, or the mag got "lost" along the way, that happened a lot during the magazine ban days. Back in the old days, we had to store mags seperately from the gun to keep them from getting lifted, and that often resulted in unintentional short changing people on mags. If you had brought that up during the transaction, the shop might have done right by you on it, or that might be one of the reasons for the discount. One of my used kahrs came with the wrong caliber mag, I just sold it and bought the right ones.
You still got an excellent deal, just not as great a deal as you thought. I would not worry about it. Lots of people pay MSRP on stuff and are quite happy.