Car handling is sloppy even with rear sway bar - BK MPS

Looking for some insight into my issue that's been plaguing me for a while now.

Basic rundown of my issue, have a Whiteline RSB coupled with moog endlinks. Initially when installed felt great - felt firm and handling/turning felt much sharper. Exactly how a rsb should feel. Fast track a few months down the line it feels sloppy like it's not even on. I also had it checked out at tunehouse about two months back as it was clunking, and they fixed that and managed to retorque everything, resulting in restoring the feeling of how a rsb feels on a car. Now, the last few weeks, the sloppyness has returned and handling has gone to sh#t again. I can't figure why and what's up.

I went under today to have a look and end links and brackets were already tight as can be. However I did notice that the moog endlinks could quite easily swivel at the joint connecting the rsb. Does that mean they've stuffed up?

Anyway just looking to see if anybody has experienced handling going bad or at least like it feels there is no rsb installed, some time after one is installed.

Interesting issue, have the aluminium rsb stops snaped or come loose ,???? the allen key screws are only threaded into aluminium and be careful not to overtighten (loose purchase) .
The end links are ball joints and should be able to swivel ,but not real easy (remembering that they are greased joints).
What rsb hole are you using ,(stiffest or std).?????

Everything looks like it's in place, including those stops. I'm using the stiffest setting. To be fair, and to clarify, it's probably better in saying it's not completely 'sloppy', in the sense that the car would most likely be worst off without it on, however still feels like it's not really there as that firm/sharp/rigid feeling is missing.