Dear Mr. Robert,
I would like to apologize for the delay in shipping your order. Due to excessive demand last month, it seems impossible for us to process all the orders in time.
However, we sent your order earlier this morning, and we are sure you will receive them by tomorrow.
Please accept our sincere apologies again for any inconvenience we have caused you.
Thank you very much for your consideration.
Yours truly,
NKC Co.