Well, no you didn't order from Paypal, which is a payment method.
Were you on eBay or another online sales site?
EBay has thousands of independent sellers. Some other sites that take Paypal also have many sellers, while some are corporations.
So, first you have to identify the site you bought from. This information is probably on the invoice you paid.
Then if there are multiple sellers on that site, you have to identify which person you bought from.
Ycu can then contact the seller and ask for the date of shipping and the Delivery Confirmation number of the parcel.
(Not every seller uses Delivery Confirmation, but it puts the seller on notice that you are serious.)
If you do not have a useful response, like your money or your book by April 10 (Day 41) you should start a Item Not Received dispute through the Paypal Resolution Centre.
Do not leave it longer, PP only allows disputes to be opened for 45 days.
