You have to understand that big account would not deal with you if you will demand your payment right away. There is no way i will go chase Burger King/McDonalds/Police etc. accounts to pay us right away, because there is a chance that they will find another vendor who will agree to work with net 30/45/60. Average Joe - yes, pay right away, its what i said in previous post.
Therein lies your problem. No one HAS to do anything, be it understand or play by their rules.
Would you define "big account" ?? Is it someone will known..... or someone who spends large amounts with you ??
Regardless for whom we perform work, they pay on our terms. Had one recently, we instructed them of our terms once again, they balked and I thought they left, but they just placed an order and said they would pay upon receiving the order.
If you, or any other shop here sets down terms, you either heed by them or break them. That's your call. If you're afraid of losing a customer because you won't finance a large company, that's on you for running scared. We deal with some hefty companies, and they all work within our terms.
Something to be said about presentation, not only how you present your own company, but how confident you conduct yourself..... not to be confused with cockiness. Put them in the know by telling them up front how you expect things to go. Any deviation will be dealt with accordingly. No need for you to be on the 'defense' just because you're a little guy or something.
If they come to you, its for a reason. Is that reason because you're good or because you give good credit terms ??