Good day [recipient],
It is with a heavy heart that we must let you know that [date] will be the last day that you can visit our [shop/business/office]. After that date, we will no longer be offering our [product/services] to the public. We want you to know that we did our best to avoid getting to this point but the circumstances pushed our hand.
Still, we would like you to know how much we appreciate your loyalty to us. We couldn’t have lasted as long as we did without you. It is your interest and your support that made this [shop/business] a reality.
[Name of sender]