It seems like some other folks have reported a reduction in hours/shifts after complaining publicly or using their real name. It isn't at all surprising. The comments on this Inside Higher Ed article seem to suggest other people have experienced a reduction in shifts after such. I haven't experienced this, but I've also avoided signing petitions or complaining with any account that could be linked to me.

I don't trust these people at all.

https://insidehighered.com/quicktakes/2018/01/05/ets-cuts-pay-some-test-raters

On top of that, it appears that they are participating in a practice a lot of tech companies do -- hire a bunch of people on h1b visas -- pay them less (while promising more than probably any of us ever got.) This is easy to find with a search for h1b and educational testing service. I would love to report them.