Anyone ever dealt with a C.O.D.?

thats what i was hoping they leave a card and i can go pay with a credit card. since i figured mail carrier wouldnt be allowed to carry cash. besides she NEVER knocks always just leaves a note. i think she has it prefilled out since i am home everytime she delivers something that needs signing
A good number of them are on such a tight time schedule they have no choice but to just leave a card.........