Client Difficulties

I have a client who misses deadlines, needs reminders, and cancels without 1 week notice.
I want to have boundaries around when things are due and what the cancellation policy is including clear consequences.
I have come up with several ideas, but haven’t been able to identify ones that feel good and like they’re coming from a loving place.
They feel like they’re coming from a place of a lot of rules and punishing the client because I feel annoyed at their behavior.
I have the thought that these are the rules/guidelines of my business and I am happy to keep clients who respect them and happy to release clients who don’t.
Where I get stuck is on communicating these guidelines to the client who is not following them.
How can I have loving kindness in the F line to drive my actions to communicate boundaries?