I would say " due to ongoing(or chronic) payment issues and a general air of disrespect towards myself and my business I will no longer be providing care for xxxxx. The last day of available care will be xxxxx. Please note that all fees are due up to and including the last day of care regardless of attendance. I wish you all the best in the future. Sincerely the best daycare provider you just lost" Hopefully you have a deposit for when they try to jack you.