Very simple. Pay them on time, not even one day late, with the payment method your vendors prefer. The word will and does get around to those who do and those who do not. I hear every day from 1000s of 170 nations about those who do not pay their vendors on time and/or who insist on not paying in the method that the vendor prefers. Unhappy suppliers can look elsewhere.
Odd, huh? Much of the time, we hear ... the customer is always right which I tend to agree. Our customers are extremely important to us, so this post has nothing to do with our customers. This topic was discussed among IP communications industry persons on a teleconference call early this week.
Check out what the government of United Kingdom is doing about it at Prompt Payment Code.
... browse some of our team's other blogs at http://blogs.didx.net and http://blog.tmcnet.com/monetizing-ip-communications/. You're welcome to comment, contribute, and collaborate any time.