I've had this for a couple of years now and until yesterday worked great.  I bought the pack with an adapator TL-PA4010 and 2 extenders TL-WPA4220. At the same time I bought a further AV600 powerline extender (same code) but havent used the extra one, until recently my son wanted better wifi in his room. 

So yesterday i tried to connect it to the other extenders, it wouldnt work, so i started again with resetting all and doing a set up for all 3 extenders.  And its basically resulted in all 3 extenders now not working at all and unable to access the internet.

Ive an ethernet cable linking the virgin media wifi hub to the adaptor. Ive then tried to pair the adaptor to the first extender, next to it which linked, then the first extender to the second.  I got 2 of them to pair but the third wouldnt.  Even if i'm stuck with 2 extenders, thats fine (I just want it working!), but its not accessing the internet when its up and the top two lights are on on the AV600 extenders.  Devices like my phone and laptop are not recognising them. 

I keep seeing mention of 2g and 5g, but where do you see this?, as there nothing on my virgin media hub on this.

 Would appreciate it if anyone can help.