Neither is correct. In this case, you need the following construction:I am wondering if you had received the letter
I am wondering if you received the letter already.
I am wondering if you HAVE received...
As far as the second part of your post is concerned, if you say a type of actors, it refers to ONE type of actors. If you say typeS of actors you refer to many, or more than one type of actors. That is, in your case, you should say TYPES OF ACTORS.
Oh, this sounds pretty but I'm in a hurry
Student or Learner