Some one wants to upgrade their shipping after paying in full, how

[pumpkin*king]

more than 3 years later but I am now in this predicament...They already paid for the $600 item which I had listed for Priority Large Box 1-3 day free shipping on my end for all my listing, now they asked me to upgrade to overnight but they say they would pay the extra $50. However they already paid and now I cant invoice them. Without Paypal I have no idea how to do this, Any advice helps

[disneyshopper]

You have 2 options.  You can give the buyer your Paypal email address and let him/her know what the extra cost will be for Priority Express, and s/he can use the SEND MONEY option to send you that amount, or you can ask for the buyer's Paypal email address and then you send a MONEY REQUEST using your Paypal account.