Cancel the plan at the end of the billing period

curl -X POST 'https://api.expiryedge.com/v1/cancelSubscription' \
  -H "Authorization: Bearer $EXPIRYEDGE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "reason": "too_expensive",
  "feedback": "We are consolidating tools at Northwind Dental."
}'

{
  "status": "success",
  "message": "Subscription will be canceled at the end of the billing period",
  "cancel_at": "2026-10-15T00:00:00.000Z"
}