Dynamix keystone to PDL600 faceplate adapter

Hi

I didn't want my first post to be asking for help but I'm at a lost as to what is going on here.

I am currently in the process of sourcing all the materials needed for an infrastructure upgrade in my house and have purchased some Dynamix cat6 keystones along with some PDL 600 series faceplates as well as the little adapters that allows third party keystones to fit into the PDL faceplate, my problem is the keystone with the adapter clipped onto it just sits in the faceplate and the smallest amount of force pushes the keystone along with the adapter out and I can imagine when I go to plug in a patch cable the same will happen.

I feel like I'm missing something really obvious here, do I need to glue the adapters to the face plate or something?

And by faceplate I mean the bulky "sub-plate" which screws into the flush mount not the "finished" plate which clips on.

I intend to return to the supplier tomorrow and get their opinion on it but thought I would ask here first and perhaps save myself the trip.

Thanks.