You need to work on your communication with the customer.
We all have very busy lives, and you say one thing then hours later after jumping through hoops to do as you request can not complete the job due to details left out.
This is the first time and you did it again a 2nd time.
Communication is key in every part our lives, please take the time to work on this.
Not good for your business as some of my friends have been informed of the communication issues.
You are the expert and as a customer I expect you to be as this is not my field of experience.
Please get it together.
I don't understand when you say we need to work on our communication, we kept you up to date throughout the day. We have no control of our parts delivery. We informed you in plenty of time that the part would not arrive on time so you could make arrangements to pick up your children from school. I guess you forgot that we "communicated" to you last week when we advised you that we could not do your smog inspection as your check engine light was on we could have just run it through and failed it and charged you for the test but we didn't. Unfortunately, it just doesn't seem that we can please you with anything.