Keep customers informed
"No news is good news" does not apply when things go wrong.
Source: Sales trainer Amy O'Connor
When things go wrong, you must over-communicate with your customers.
When people feel stressed out, they begin thinking the worst. And what feels like "over-communicating" to you, feels like reasonable communication to your customer.
Even when delivering bad news -– and especially when things go really wrong – keep your customer in the loop.