What does this app do?

I have had this app installed for a couple weeks and havent noticed any calls being blocked. The look up number feature is nice but most times Hiya says the number has no complaints but I KNOW its spam on other users comments say the same.
Also, its too hard to add multiple phone numbers to Hiya blacklist. I have a contact on my IPhone called "BS Callers". I want to import the entire contact but I cant. I have to import 1 by 1.
Still looking for a good app for spam phone call blocking.

pikesan about Hiya: Spam Blocker & Caller ID, v2.0