Apple does not seem to think the issue is widespread and happening to a lot of people.
and it is responses like this, that make my blood pressure go up. this guy is not listening to my problem at all. although to be fair, he is from iTunes store and not a tech advisor.
Greetings from the iTunes Store! My name is Justine, your iTunes Store Advisor. First and foremost, I would like to extend an apology for the delayed response to your email. Thanks for your patience.
I’m sorry to hear that all of your songs were disappeared on your device and saw an exclamation point next to the songs. I can imagine your eagerness to get this sorted out and I sincerely apologize for the inconvenience. I will be happy to look into this for you and provide you with all the information you need regarding this matter.
Eileen, please know that the ! mark means that iTunes is unable to locate the original file and as iTunes can not locate the item it can’t be played. The good news is that these songs are probably not erased; however, you will need to help iTunes locate it. I found a few articles that explain how to search your hard drive for missing purchases:
No content shows up in iTunes after updating
http://support.apple.com/kb/TS1967
This article may also be helpful:
Instructions for finding missing music and video downloads
http://support.apple.com/kb/TS1408
If you are unable to restore all the items that have a ! mark next to them, you may be able to re-download eligible content using the steps in the following article:
Downloading past purchases from the App Store, iBookstore, and iTunes Store
http://support.apple.com/kb/HT2519
Please understand that not all items can be re-downloaded for no additional cost and any items removed from the iTunes Store or modified from the original file you purchased will not be made available for you to re-download.
I certainly understand how valuable your purchased files are to you, as Apple is not responsible for lost, damaged or corrupted items and as items available for re-downloading within the iTunes in the Cloud purchases can change at any time, I would highly recommend backing up your purchases. This way if files do become lost, damaged or corrupted you can restore them. This article explains how to create and maintain an up-to-date backup of your iTunes library:
Back up your iTunes library by copying to an external hard drive
http://support.apple.com/kb/HT1751
I hope this information will help you. Thank you for contacting iTunes Store Support, have a great day.