fraud?

Description

Hi,
i hope someone can help me. I sold my iphone on Facebook and the buyer sent me a phone number that i could request money on paypal.
When i open the app, it shows me that the request is pending and it has a red color. I got an email from an email address paypal careline and it says that my money is on hold. I shipped it but after that i was suppose to be able to add the tracking number and i did not get any further notification from paypal. I think the email address is not even real and i just shipped a brand new iphone to someone and i am scared that i am never going to get paid. Could you please tell me some advise????
Thank you
Esther