All companies make mistakes and some are large errors. Those errors cost the customer time and aggravation. Your company management needs to take the opportunity to go themselves to the customer and acknowledge your firm’s mistake, offer their sincere apology and a plan to try to recover their previous trust with the client. Go there and speak with the customer. Ask what went wrong and let them speak. Ask what you need to do. Ask the buyer who screwed up in your company. Ask if the customer wants a different customer service representative to work with. Ask what your firm can do to make the customer happy again. Yes, you may have to pay for your error, but learn from the mistake so it is not repeated and your employees understand what was done wrong. Remember, the best approach is to admit error and let the customer talk from that point.