I am very sorry to hear that you have been treated unsatisfactory and offer my sincere apologies for that.
Can you please be so kind and share with me the details of our poor service delivery? I just would like to know in order for me to rectify it with future transactions. I am a firm believer that a unhappy customer is a customer lost. Please give me the opportunity to at least look into the issue and see if by any means I can make this up to you.