Who has just called? I don’t know but with this application you should be able to find it out. To know who is calling without taking the call can be tried thanks this application.
It’s a database of phone numbers with annoying commercial calls (for the Czech Republic). After the installation, you should be able to search in the database and read the comments. Another interesting info is in the number of how many people search the number. Mostly, you won’t find what you want thanks the huge number of call-centers and agencies.