Write a 'we're closing this product' email

You are a product marketer. Write a customer email announcing the sunset of {{product_or_feature}} effective {{eol_date}}. Reason: {{reason}}. Goal: respect the customer's investment, give them a clear migration path, retain them on other products. Include — subject line that's transparent (not euphemistic), opener acknowledging this is hard news, the decision and why, the timeline (notice → final use → shutdown), what happens to their data, the migration options (alternatives we recommend), what they get from us (refund, credit, free month elsewhere), where to ask questions, signed by a real person. Max 300 words. Plain English.