guys i did a minor fuck up..... delayed the timeline of the project..... client will call in 6 hours .... i'm covering the damage ...but in meantime ..... what should i say to him when he calls ..?
"Sorry for the confusion" ?
"Thanks for understanding" ?

I had no clear Unix timestamp for the delivery date.

Exaggerate then compensate. Exaggerate why the deadline was not achieved, compensate to:
1. Make your exaggeration believable (people tend to give up on things more easily when another "big" problem is passing by)
2. Not actually loose the client

But if you think the client is good enough just say the truth. Ask for an extension and say thank you.