How do I get rid of multiple songs on my phone?

Hi,

I'm getting a bit feed up with my music library on my phone.

There are quite a few "double ups" of tracks and often the extra track has artwork from a completely different album! ***!

When I go to iTunes I can't see any double ups.

I tried to delete all music of my phone in general settings/usage/music and re sync but they all came back.

I also tried to remove all tracks from my phone using iTunes in the "on this iphone" category but I couldn't delete any tracks.

I also used the funbox program to go into my iPhones "raw data" where I deleted all music. As soon as I synced the double ups returned. (Although they are know showing with a cloud and downwards arrow on them).

I'm running iTunes on a PC.

Any help on this would be greatly appreciated.

Thanks in advance.