Check the email is not a scam first.
1, Paypal emails address you by your full first and last names.
2. Paypal emails don't have links to log in and enter sensitive log in / financial info.
Go and log in normally and see if there really is a payment in there and if not then the email was a spoof.
If the payment has gone out of your account and you don't recognise it then go and click on the resolution tab in your paypal account and file an unauthorised access dispute.
Then go change your paypal password and security questions etc.
Advice is voluntary.
Kudos / Solution appreciated.
