I just received an email that someone purchased something on my iTunes account from a device that is unassociated with my account. I have not purchased anything. When I tried to report a problem, the link just goes to a google search page.

That certainly sounds lime a phishing attempt. See the info below for steps to identify bogus emails.

• Apple does not include document, or PDF files to download.
• Apple would not refer to you as Dear Customer, Dear Client, or anything other than the name on file for your account.
• Apple would not have such horrible spelling or grammar. 
• Apple would not send a message to “Undisclosed Recipients”. 

It is a phishing attempt. Do not respond. Do not divulge any personal or financial information. You can use the address below to forward the suspect email message, as an attachment to Apple.

reportphishing@apple.com

The links below has information to help identify fraudulent emails.

Identifying legitimate emails from the iTunes Store

https://support.apple.com/en-us/HT204759

Sounds like it is phishing. In a message Apple will always address you by your real name, never by your email address or Dear Customer. Also the sent-from address should be @apple.com or @itunes.com Additionally Apple does not send attachments.

Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support

Forward it as an attachment to reportphishing@apple.com