Always Investigate Complaints - They Might be Legitimate

Many companies use complaints to delay or avoid making payment, and no doubt you have had, or now have, or will have customers that use this tactic - but you shouldn't become so suspicious that you treat all complaints as groundless and all customers who complain as nuisances or bad payers.

You should never lose sight of the fact that a complaint might be justified, and that your customer might have a genuine grievance. ALL complaints should be thoroughly investigated - despite the fact that this will inevitably delay payment - and pending the result of your investigation, all collection activity against the complainant must stop.

If you are not totally in control of the collection process, make sure that everyone involved knows that there is a complaint, and that all collection activity against the complainant must stop. There's nothing worse than dunning a disgruntled customer.