DONT Read some crap comments abt fbi.. they got no shit to do with it as u havnt made payment ur self
just calm down and read this
i dont know abt ut status of pp so most likley
u have got 3 option
1) if ur paypal is fully verified and have no dispute ever before .. respond to it
2)if ur paypal is verfied but u have small dispute before ... dont do a shit
3)if ur paypal is unverfied/or u have many dispute before or u are too scared to take risk of first 2steps.. go to resolution ceneter
and select resolve case and their select that u have refunded the payment
3rd step is 98% success ad saftry of ur paypal account but in this u wont get a shit
u can use third step even if u have a verfied pp
this should prbably solve out all ur problem