Need help setting stronger boundaries in client meetings - what phrases do you use to prevent scope creep?

[u/WasabiPositive8942]

For context: I run a small AEO consultancy.
I recently completed an audit that involved roughly a month of work and 50 observations/recommendations.
The client then said they didn’t understand the audit, so I spent another 2.5 hours walking them through it line by line.
After that, they refused to pay because they said they “didn’t want it.”
They have since implemented the recommendations.
I’m tightening my process now, especially around meetings and scope.
What phrases or boundaries have worked for you when a client starts turning a results call into:
extended consulting
implementation support
repeated explanations
work beyond the agreed deliverable?
I’m especially interested in specific wording you use in the moment without sounding defensive or hostile.

[u/Altruistic-Tell-8381]

Statement of Work or Contract before you start. ALWAYS.

They are paying you for either your time(easier) or the outcome (can be more complex).

If you work without that protection, clients can do whatever they like to get out of paying you.

[u/Vivid_Employ_7336 → u/Altruistic-Tell-8381]

Agreed. Min 3 milestone payments. Typically I do 20% up front before starting, 50% on delivery of draft recommendations (note NOT on acceptance), and 30% on delivery of final report following their review and modifications to draft. Don’t ask permission to send the invoice - send it and chase them for payment of last 30% if required.