Dear :

Thank you for your inquiry of [date].

I am sorry to inform you that the [products] you need have been out of stock, and we do not expect another delivery until [date]. However, we do have a consignment of [products] which we recently imported from [country] and can offer you as an alternative.

Please inform me if you would accept these [alternative products] or prefer to wait for the [products] that you initially wanted.

Sincerely,

[name]

[title]