I see this thread exists under guides and tutorials but nothing there that would explain things. Im new players again...started couple days ago but cant use any New Player codes

if you can remember the name of ur old account you can contact support and they can get you access back to ur old account, even if it was not attached to a plarium account or email (it will take support a while to do it for u but will eventually happen) if that helps

Seems ages ago that a new promo code was in circulation. 

Are you using the same email address for the old and new accounts?

Hello there, how are you doing? 

Well actualy it´s pretty easy nowadays to get this kind of information, if you google "Raid Shadow Legends´ promo codes", you´ll see there are many content creators with their own websites which allows everybody to see the active, inactive and expired promo codes. By the way a RSL Series has come to an end a couple weeks ago, try to check that out, you´ll get some juicy rewards from it. 

To be more specific, visit Hell Hades and DeadWoodJedi respectively websites, you´ll get advantage from it for sure. 

I hope it will help you a bit. Have a great day!!