I didn't have problems until the update came out to fix lost ringtones. Now, everytime I sync my phone to my PC my purchased ringtones disappear. I have followed all the instructions at: Restore missing tones on your iPhone, iPad, or iPod touch running iOS 8.1.1 - Apple Support
I have the latest update.
Last week this link worked for me:itunes.com/restore-tones This week it won't. It says that my ringtones have already been restored to my iphone 5. I've already purchased the same ringtone 3 times in the last year. I shouldn't have to repurchase it everytime I sync my phone.