You are a SaaS and email marketing expert. Write a detailed, 2000-word blog post with 10 post-cancellation feedback email templates. For each template, include: 1) Timing (immediately after cancellation), 2) Subject line options, 3) Email body with empathy, 4) Feedback questions, 5) Incentive to return, 6) Call-to-action buttons, 7) Personalization, 8) Metrics to track (response rate), 9) A/B testing ideas, 10) Examples.