The exploit is really gettin' old. People will repeatedly invite someone to a voice chat in order to prevent them from doing anything in PVP matches. It might be the lamest thing in DCUO.
Same thing happened to me in Legends PvP years ago. I reported and I never seen the player again anyway. But as Stanktonia said, put on ignore and continue with the match. That's the best option right now if it won't get addressed.
Not worse than coward way of atomic cheese in arena and acting pro. Then wanna insult people that does beat them. Harassing for scrimmage. They still forget that screenshots and videos exposes toxic people.
There is a setting you can flip to ignore chat (and any of the similar) invites you can receive. It's not about having to ignore each person, it's just a one-time flip. This was added specifically for this situation.
I will certainly make use of this feature. However, I would still like to see players in PVP instances unable to send such invites, in case not all members of your team are using the toggle options. It's always better to remove problems like this, rather than placing the onus on the victims.