The way I understand it, British English is more flexible than American English when it comes to whether or not a collective noun takes plural or singular. This is what the Oxford Dictionaries has to say about “media” (slightly rewritten by me): In the sense ‘television, radio, and the press collectively’, media behaves as a collective noun (like staff or clergy, for example), which means that it is now acceptable in standard English for it to take either a singular or a plural verb. source https://en.oxforddictionaries.com/definition/media

From an American here, technically it should be "media say" but very often I hear (or even say myself) "media says."