Check in Mail –
[Name, Company Name & Address here]
I acknowledge the receipt of your invoice no. [number here] on [date].
I want to tell you that I have double checked my records and found that I have mailed you the check [no. here] for an amount of [amount] for this invoice. I mailed the check on [date].
If you do not receive the check by [date], please inform me as soon as possible. I will send you a new check for the last invoice.
Encl: [Enclosures List here]