How to get music I purchased from iPhone into my PC's iTunes?

I am using an iPhone 5 (iOS 8.1.2 or so, haven't downloaded the latest ones as I'm concerned with memory space), using an Asus G74SX laptop with windows 7, and probably not the latest version of iTunes either.

Due to the difficulties of finding CD copies of music I like where I live, I've been downloading a few albums from iTunes via my iPhone, and thus the purchases are on my iPhone but not yet in my PC. I want to sync it up so that my PC's music library matches with my phone's music library.

I have tried File>Devices>Transfer purchases and it doesn't seem to work - it only syncs up apps and not my music. Another thing to note is that some of the music on my PHONE seems to have an exclamation point on them (see image below), even though I can play them on my phone just fine; so not sure what this means... I know the music I have bought but not yet downloaded displays as an empty dotted-line circle.

It also doesn't really matter whether some of the music has an exclamation or not, as none of the new music I have bought from iTunes via iPhone are not being transferred to my PC.

Am I missing some sort of setting from transfer purchases that is supposed to enable me to transfer music purchased from my iPhone into my PC?

Hope my explanation was clear enough. Looking forward to some answers and solutions!

Nanda