Due to my personal negligence, the following goods were not shipped on the fifth. Please accept my sincere apoloy. I will arrange the shipment of the goods today. And they are expected to arrive at the shop by the seventh.
Because of my own reason, the goods are not delivery on time on 5. I really sorry for that. I will arrange the goods today. The goods will reach your shop on 7.
I apology for my carelessness which brings you much trouble. I'm sorry to give/bring you so much trouble just because of my own carelessness/fault/neglect. I am sorry to cause you so much trouble because of my oversight.