Songs won't delete/appear

It seems every time I connect my iPhone to my laptop my music gets totally messed up. I've now got several issues.

1. There are some songs (which I hate and don't listen to any more) that I just cannot delete from my phone. I've unticked them and deleted them in My Music on iTunes and as a result they no longer show up, apart from on my phone itself. When I try and swipe to delete on my phone the delete option just doesn't appear and I can't access them on iTunes any more as I already deleted them there. When I search for them the only options which come up are the songs in the store where it says 'Purchased' next to them, but I can't do anything with that. I'm at my wits end, I hate having these songs I don't want on my phone, does anyone know how to finally be rid of them?
2. On the other hand, there are several albums/songs which just keep being removed from my phone. It mostly seems to happen to items I've bought directly from the store whilst on my phone, not my laptop. For example, when I connect via USB to my laptop and sync, despite making sure I've selected said albums, I'll end up with only one song from the album on my phone. If I press 'Show complete album' it brings up the rest of the songs with a little cloud icon next to them and I have to download them all over again, I shouldn't have to keep doing this every time I connect my phone to my laptop, it's totally ridiculous.
3. I never seem to be able to delete anything permanently, always, somehow, things that I imported from CDs or bought years ago keep popping up and I have to manually delete each one on my phone one by one. How is it not possible to get rid of something once and for all?!

I have an iPhone 4S with iOS 7.1.2 and the latest version of iTunes on my laptop. I have already made sure that 'show all music' is turned off in settings.

Any advice greatly appreciated.