Why is 2013 Rx 350 Lexus 117k miles Control arm keeps failing?

CarMax serviced my vehicle this morning and they discovered that popping nose is coming from the driver side ball joint, it's failing. I'm going to speak to the Service Manager, because I don't understand why they didn't replace all associate parts when they discovered and replaced the failing control arm a few months ago.

I picked up my vehicle last night, the paper work shows that the Problem was driver side ball joint, they replaced that and the lower control arm, this is the third time. I'm going to speak with a Manager about having this vehicle replaced.