Double or Triple Account player(s)? Is it allowed?

Hello!

I'm in a game (#4148955) and i feel, that there is a player with a "double account". I think that the Player "user10314591" (here: Finland) is the same player as "user10314558" (here: Sweden). They are almost online and acting at the same time.

According to their names, they must have been registrating almost at the same time. If you look at their statistics, they are almost the same rank and also acting the same way somehow.

In fact there are other things too and I feel, that it is the same player. Is that allowed? I can't imagine, because it is not fair.

How should I react or is there a certain moderator, to whom I should report this?

Greetings, Meks