If you cannot pay a bill in its entirety to an important vendor, even in lean times, try to pay a portion of it. This is not a normal practice but once performed your effort will impress nearly every vendor you hire. Most companies do not want to make partial payments to their vendors because they do not want to insinuate they have problems paying bills, so they decide not to pay anything. What type of thinking is that? This does not make sense, causes prices to rise and creates animosity between customer and vendor.
Be honest with vendors; be upfront. One option during hard times (tight money) is to be honest about your difficulty to pay your vendors; work with them. Call your vendor and tell them you are waiting on a payment not yet received. Tell them you want to get them paid but cannot today pay all of it, but you are willing to send 25% or 50% now and will forward the balance within 7 days or 10 days (you pick the projected deadline). Most companies will not do this because it is time consuming, but when you personally call and offer to do this, most small vendors who need to meet payroll will greatly appreciate your efforts. Consider who you want to try this method with but do not ignore good vendors who are valuable to your firm.
Continue to pay your vendors even when you are cut off from credit. Even if you are cut off by the vendor which they may have to do given the rules of their own bank, pay them something. You will at least show some integrity by your effort. Few customers in cash strained situations make an effort to pay past due invoices in any amount. You as the customer do not have to do this, but certainly it may be the honorable thing to do for your very small vendors which rely on your payments. Consider this fair approach with select valuable vendors.
Even with partial payments you should always pay-off your vendors entirely. It may take several months of partial payments to pay off vendors, but you will be establishing your integrity through your hard times and they will remember you paid them, even when those payments were short. Few companies make partial payments so when you do after explaining your problems, your vendors will appreciate your honesty. Your efforts will pay off for you in the future.