If you're reading this you're either working for Fabletics, about to call your legal team (you have one?), are the legal team (really, you took this?) or are just interested in the legality of all this.
Firstly, I'm not a lawyer, however there is plenty of past precedent about so called 'gripe sites', and therefore I'm confident that this site will stay where it is. Let's look at various avenues;
No, it isn't. We clearly state that there is no connection to Fabletics or JustFab UK. I don't think anyone is going to rationally argue that we are 'passing off' or that this site could 'mislead' someone into believing they're visiting the Fabletics site due to 'initial interest confusion'
Use of a trademark in a domain name is acceptable where it's not an abusive registration, otherwise sites like paypalsucks.com would have disappeared a long time ago.
Nominet Decision (DRS 08527) is often referenced in cases like this - however the decision of the Nominet expert was that it would have been a bona fide criticism site had it not been rendered Abusive by the domain owner receiving revenue from advertisment. In contrast look at the high profile 'opticalexpressruinedmylife.co.uk' ( in which the ihateryanair.co.uk case was of course dragged up ) - no adverts, just criticism.
No ads here :D
In the first instance please contact Nominet, who will introduce you to their Dispute Resolution Procedure.
If that fails, all we really ask is the following;
If you do this, we will gladly remove this site, as its raison d'être would no longer exist.
Now, that isn't so hard is it.