I would discount with a nice letter. Your problems are not her concern really.
I apologize. We want each person we do business with to walk away feeling satisfied, and that apparently didnít happen in your case. Please give us another chance; we want to make things right.
Although we try to cover all the bases, we arenít perfect. We depend on customer feedback to let us know where we can improve. Please contact me at your convenience so we can discuss this further. I do hope you accept our apology and see fit to do business with us again.
At the same time I would let all your clients know you have a new addition too. Take some pictures and send them out as post cards saying thank you for being a loyal client.
At times I think I get to know my clients too well. They call me and fuss at me... I do my best to fix it.
Granted, I allow time for this too happen. You should have done more to get the job done. There are times when I do not care what happens but I make it right. One of the problems of being solo frankly