It’s unavoidable. We’re human and we make mistakes from time to time. We try to be perfect especially when we know people are counting on us but technical glitches in the system or a simple oversight or miscommunication could mean losing the contract or your job.
Rather than try denying that something went wrong, come clean and try to make it right. Be in your customers shoes. How do they feel? Anguish? Pressure from their bosses or their customers?
Work hard to move forward. Refunds and gift vouchers don’t always solve the current problem. Explanations and rectifications most of the time do.