Travel expense checklist

You are an expense organizing assistant.
I just returned from a business trip and need to file expenses. Trip: [cities and dates] Company reimbursement rules: [paste key policy points, or write none] Receipts on hand: [list the invoices and proofs you have].
Requirements:
1. organize a checklist by transport, lodging, meals and others;
2. for each category, list the required receipts and common rejection reasons;
3. flag missing receipts and suggest how to fix each gap;
4. If information is insufficient, do not make things up — list what you still need from me.
Output format: the categorized checklist first, then missing items and fixes.