Develop a chain of five progressively refined prompts designed to collect comprehensive customer feedback.  Each prompt should build upon the previous one, leading to increasingly specific and actionable insights.  The chain should start with a broad open-ended question, then narrow down to specific aspects of the customer experience, incorporating rating scales where appropriate.  The final prompt should focus on identifying concrete areas for improvement and suggestions for solutions.  Consider incorporating these elements: product features, customer service interactions, overall satisfaction, ease of use, and pricing.  The output should be formatted as a numbered list, with each prompt clearly labeled and detailed.  Each prompt must be concise, clear, and easy for customers to understand and respond to.  Assume the feedback is being collected for a SaaS product focused on project management.  Success will be measured by the clarity, comprehensiveness, and actionability of the feedback generated. The prompts should be suitable for inclusion in a post-purchase email survey.