Customer Has Voiced Cancelation

Review the account profiles in your CRM, Customer Success Tool, Google Sheet, your notes, etc.
Look at their usage, activities in product, last touch, conversation history with the customer.
Determine how you can save the account.
Reach out to the customer via phone and confirm the cancelation is accurate. It is possible it may be wrong. If a direct number is available, then email and book time. Suggest 3 times you are available to meet with them OR Book a meeting on your the PoC’s calendar 10 days out. Do not just supply your calendar booking link, the chances of them booking are low.
Once contact is made or a meeting booked, prepare for the discussion with data/screenshots/insights to change the situation.
Design a plan with your customer to get things back on track. Document this in a formal Success Plan with tasks/to-do’s for all involved.
If customer is not receptive, escalate to management. But make sure to complete steps 1-6 before doing so.