A small commercial business in Canada was preparing a mailing to its customers when the letters and the envelopes were mismatched, causing 500 of 1000 letters to be sent to the wrong recipients. The letters contained the name and mailing address of the clients as well as account numbers and account balances.
The business has discovered this error as clients called to report receiving the wrong letter and expressing concern that their information has been breached. Which of the following is the most appropriate next step to take?