16-04-2018 9:00 AM
There may be a problem at the seller's end. Have you asked them to check in their Paypal account? If that payment comes back ask the seller to send you an invoice from their Paypal account using the Send & Request link at top of the page.
If all else fails ask the seller to refund your money and buy elsewhere. If they refuse you can open and escalate a "not received" case to get a full refund.