IDEA: Treat customers ethically if you wish to keep them.

Treat your customers as ethically as you would want to be treated yourself.  For example, do not cut the customer off from buying for past dues.  He may not have your invoices.   Call them and courteously ask for status of pastdue invoices.  Treat them with respect.  If they have a credit limit, politely call them and let them know well before you cut them off that they are approaching their credit limit.  Give them time to resolve the matter without disturbing their outgoing shipments they are depending upon.  If you are dealing with buyers there at the customer who only deals with verbal purchase orders, reiterate all of your verbal orders in writing in an email and request that he say he agrees to the written contract, even on an email.  Give him the business and do not hesitate to take the order, but do it in writing, politely.  These are just few things that you can work around to respect the customer.