How do you Say this message was sent out by mistake in Russian?

I have a woman who is renting from me, unfortunately her son passed away and she doesn't speak English. I am trying to write a note to her about a letter that was sent to her by cleaning company.

I just need her to know that:

There is no window cleaning scheduled for the 5th of July. The message was sent to her by mistake.

Could you please help?

Thank you.

На 5 июля не запланировано мытьё окон. Сообщение было отправлено вам по ошибке.

Thank you so very much!