A Bill of Exchange is a financial instrument which promised to pay money after a fixed period, was signed by the person drawing the instrument up and the 'acceptor', who was the person responsible for paying the money signed it to prove they agreed to it. There would usually be a three day grace period, to allow the acceptor time to get the cash together when the bill is presented for payment.
In 'Wall Street, A History, Charles R. Geisst, Oxford University Press 1997, ISBN 0-19-511512-0.' Geisst writes:
When the Second Bank of the United States went out of business in 1836, many states quickly began to feel the economic pinch...Many states had used regularly used the Bank of the United States to support their bond issues. When it failed, they were no longer able to borrow from the bank to pay their interest, and eight states went into default (Arkansas, Indiana, Illinois, Louisiana, Maryland, Michigan, Mississippi and Pennsylvania, in addition to the Florida territory)...On the other side, the states' refusal to pay interest brought opprobrium down on the entire country. Unfortunately, the United States as a whole was achieving the same sort of reputation abroad. Its image became so tarnished that the British dubbed their former subjects 'a nation of swindlers'.
Dickens was writing A Christmas Carol in the early 1840s, so this view would be topical and current.
So essentially Ebeneezer is saying, 'If there were no more days to be counted then a Bill of Exchange which should pay me in 3 days is worthless.'