I have contacted our supplier and courier to have a check for you that due to recent busy shipping, I can not ensure you can get it on before then.
I am sorry for that. To be safer, now shall we suggest we refund you full now and you can find it somewhere else? How do you think?
I am so sorry for much inconvenience caused. We will surely keep improving in the future.
Or if you have any other ideas, you can share with me and have a further discussion.
Looking forward to your early reply.