We put a stop service on clients who are behind on their terms of payment and do not respond to our enquiries about when we can expect payment. It's a pretty hard and fast rule regardless of who the client is.

There is no policy that we respond quicker to clients who pay quicker, or are more pleasant to deal with. While I would love to say that "better clients get better service", I wouldn't be surprised if there is a subtle prioritisation at scheduling and servicing level for known "prickly" clients - the ones that are known to have little tolerance for delays and hiccups in servicing.