The issue you are having with PayPal (not ebay) is that:

a) it is a new credit card number not previously associated with your PP account;

b) the credit card IS NOT in your name but someone else; and

c) the purchase price is over $500. way over.

PP will probably slow track the clearance because of all the above to ensure that the card has not been stolen and that it is not a fraudulent transaction (e.g. someone hijacking your accounts).  This is common practice.  

Personally I think what PP is doing is 100% correct.

PS you should have done what someone else said - opened new ebay/pp accounts for your boss to conduct his business.