Devialet support??

[Pleyel]

They may consider the fact that you didn’t follow the proper sequence of replugging them as causal. Unless it locks in place, however, and falls out readily (happened to me as well, but I unplugged from Wall before replugging into Phantom - thank goodness apparently!), I think it is a design flaw. I’d escalate your issue. And I’d do it online to provide yourself a paper trail.

Intriguing: is there really a "proper sequence of replugging" and if so, where does it come from?
Imho, I hardly see the difference between plugging one side of an (unfiltered) mains cord first vs the other one, but I may be missing something.