Excel Workbook Cleanup and Transformation

I have an Excel workbook containing customer records that now suffers from duplicates, missing fields, and inconsistent cell formatting. Your task is to transform this file into a reliable source of truth: remove every duplicate entry, intelligently handle or flag the blank values, and bring all columns to a consistent, professional format (dates, phone numbers, capitalisation, numeric fields, etc.).

Once clean, the dataset must be sorted strictly by customer ID so downstream reports can reference it without extra manipulation. Please carry out the work directly in Excel—leveraging Power Query, formulas, or VBA where efficient—while keeping a clear, undo-friendly structure so I can trace any adjustments later.

Deliverables
• A single, fully cleaned and formatted Excel file, ordered by customer ID
• A brief change log or comments sheet outlining the main steps taken and any remaining uncertainties you think I should review

Accuracy is more important than speed, and the file must be ready to drop straight into our CRM import workflow.