Have had an email back from Apple :
Katy, we have already received reports for this issue and Apple is currently working toward a resolution for the issue you have reported regarding the missing tones. You will receive an email after the matter has been investigated and further information is available.
Upon checking here, the purchase of "Back In Black” was already refunded on the account. In ten business days, a credit of 0.99 GBP should be posted to the credit card that appears on the receipt for that purchase.
Now for the other tone that is missing, in the meantime, I have reposted the ringtone again on your account for another download. This is an initial troubleshooting step to try and fix the issue.
Its best to download the ringtone from iTunes on a computer then connect your device so it can be manually transferred.
If you have a computer, you can follow these steps to download it:
1) Make sure you’re using the latest version of iTunes. It can be downloaded free of charge from the Apple website:
apple.com/itunes/download
Note: Installing the latest version of iTunes will not affect your library or any items in your account that you haven’t downloaded.
2) Open iTunes. From the Store menu at the top, choose Check for Available Downloads. You can also click this link to do the same thing:
buy.itunes.apple.com/WebObjects/MZFinance.woa/wa/checkForPurchases
3) Enter your account name and password when prompted, then click the Check button.
The tone should download now. After that, you can transfer the tone back on your device.
To do so, you can follow the steps in this article:
Managing content manually on iPhone, iPad, and iPod
support.apple.com/kb/HT1535
Note: Please copy and paste this link to a new address bar of your browser to access the information
I look forward to your reply to ensure that this matter has been taken care of. But in any case the issue persists or if you need further assistance, please don’t hesitate to write us back anytime.