Account has been hacked

It seems ridiculous posting using a account that has been hacked but here goes. When i use my login credentials my account name and information are not mine. Who to i speak to to find out how to go about getting this fixed? I am still logged in on my phone and at home but when i log in at my office i get an entirely different home screen.

contact billing

https://www.plex.tv/contact/?option=plex-pass-billing