A letter of apology to customer regarding poor service performance. Whilst not agreeing entirely with the customer's assessment, it vows to improve training and the service level provided.
We spoke with the staff providing the service on the issues you raised and unfortunately they do not completely agree with your assessment. Nevertheless, we are providing additional training to the staff specifically addressing the issues. [In addition, we will send inspectors to ensure that the service level provided will meet the requirements under the contract.] If we find any additional shortcomings, we will be sure to correct them.