1/ Think long and hard about whether you actually entered or just meant to.
2/ Go and have a look in your spam folder.
3/ Go and have a look in the spam folders of all your email accounts including those you never use and the one that's set up to paypal.
4/ Did someone else enter on your behalf or did you use a paypal account belonging to someone else?
If there's still nothing after following the above steps, email me and I'll forward them to you.
Happy Mapping
