I'm using an iPhone 6S on a Windows 7 PC running iTunes 12.6.2. I've recently bought a set of wireless earphones and my iPhone is the only device i have that will work with them. I have a few issues with music on it so i'll set about them...
1) How do i remove the list of every piece of music i've ever bought from my phone?
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For example ^^ Everything listed there, in fact everything in my library isn't actually on the phone itself ... so i don't want it listed there. I only want music that is actually physically on the phone to be listed.
The music isn't even in my library on my PC. I long since formatted my hard drive since many of the tracks were downloaded. All these tracks/albums are on my iPod Classic.
2) How do i put music on my phone without removing what's already on there?
I tried syncing my phone and it said my phone was connected to another library. I can get a screenshot of the actual message if that helps but it was going to delete what was already on the phone which i don't want to do.
I followed: https://smallbusiness.chron.com/sync-iphone-new-computer-losing-music-53983.html and this didn't seem to work either - same error message.
3) Why would putting music on my phone with iMazing result in it not being there a week later?
To get round the issue in problem 2 i used iMazing which worked & didn't work.
I put 5 tracks on there for use in the gym. 4 copied perfectly fine but the 5th wouldn't. It was on my phone but not playable - gave an error message of not playable in my country. Not sure why as it played perfectly fine on my iPod Classic from the same mp3 file on my PC (it wasn't a purchased mp3 if that helps with the diagnostics?).
I then used EaseUS Mobi Mover and was able to get the final track on my phone. That was last weekend & all the music played perfectly fine. At this point the only issue that bothered me was the one i mentioned at the start in issue 1.
Today i hit the gym & all the music i put on the phone last weekend has disappeared. Yesterday i updated a load of apps and backed up the phone (all done via iTunes) so perhaps it's because of that. Either way i want to avoid putting the same music on my phone each week.
Hopefully some kind soul out there has stuck with me through this long post and can help.
1) How do i remove the list of every piece of music i've ever bought from my phone?

For example ^^ Everything listed there, in fact everything in my library isn't actually on the phone itself ... so i don't want it listed there. I only want music that is actually physically on the phone to be listed.
The music isn't even in my library on my PC. I long since formatted my hard drive since many of the tracks were downloaded. All these tracks/albums are on my iPod Classic.
2) How do i put music on my phone without removing what's already on there?
I tried syncing my phone and it said my phone was connected to another library. I can get a screenshot of the actual message if that helps but it was going to delete what was already on the phone which i don't want to do.
I followed: https://smallbusiness.chron.com/sync-iphone-new-computer-losing-music-53983.html and this didn't seem to work either - same error message.
3) Why would putting music on my phone with iMazing result in it not being there a week later?
To get round the issue in problem 2 i used iMazing which worked & didn't work.
I put 5 tracks on there for use in the gym. 4 copied perfectly fine but the 5th wouldn't. It was on my phone but not playable - gave an error message of not playable in my country. Not sure why as it played perfectly fine on my iPod Classic from the same mp3 file on my PC (it wasn't a purchased mp3 if that helps with the diagnostics?).
I then used EaseUS Mobi Mover and was able to get the final track on my phone. That was last weekend & all the music played perfectly fine. At this point the only issue that bothered me was the one i mentioned at the start in issue 1.
Today i hit the gym & all the music i put on the phone last weekend has disappeared. Yesterday i updated a load of apps and backed up the phone (all done via iTunes) so perhaps it's because of that. Either way i want to avoid putting the same music on my phone each week.
Hopefully some kind soul out there has stuck with me through this long post and can help.