Hi mvb2717,
Hey it's not a stupid question, so no worries.
I'll give you a break down of what I did and hopefully that'll help you solve the problem 🙂
Connect your iPhone with the USB cable to your PC/Mac.
When itunes opens make sure that your phone appears in the Devices section on the left hand side.
It should say the name of your iPhone, battery symbol and sync/eject symbol.
Underneath that there should be a list of sections Music, Movies etc and one of those should be ringtones.
Left click the ringtone listing. This will bring up the ringtones you've downloaded in the main pane.
Select the ringtone with the exclamation mark by left clicking, then right click to bring up a small menu. One of the options will be delete.
Delete the ringtone and then go to the file menu and sync your iphone. When i did this it removed the offending ringtone from my phone. Now go back into the ringtone section and you might find the ringtone is back in the listing with a sync symbol next to it. Select and right click and choose uncheck from the options then re-sync. You could try just unchecking it right from the beginning I just wanted to get rid of the ringtone. As for getting rid of the ringtones from your iPhone this should do it. You couls also go to your ringtones section in the general settings, (sounds), and left swipe them. This should bring up a delete button in red, hit delete.
Any way this is how I did it on my PC and everything syncs fine now.
Hope this sorts things out for you. Don't hesitate if you need any more help. Cheers. 🙂