Answer billing questions from BigCommerce and Business Central

**Objective:** For the customer with email `{email}`, show recent BigCommerce orders and what they currently owe in Business Central, looking back `{lookback-days}` days (default 90) in Business Central company `{company}` (omit when the tenant has one company).

**Step 1: Identify the customer in BigCommerce**

Call `bigcommerce-get-customer` with `email` = `{email}`. If none or several match, say so and stop. Then call `bigcommerce-get-order` with `customer-id` = that customer's `id` and `date-created.from` = today minus `{lookback-days}` days.

**Step 2: Find the receivables in Business Central**

Call `business-central-get-customer` with `email` = `{email}`. If none matches, report that the customer has no Business Central account and skip to Step 4. If several match, list them and stop. Take its `customer-number` and call `business-central-get-posted-sales-invoice` with `sell-to-customer-number` = that number and `remaining-amount.min` = 0.01.

**Step 3: Link orders to invoices**

For each open invoice, note whether its `external-document-number` or `order-number` equals one of the BigCommerce order ids.

**Step 4: Report**

* Customer: name, email, Business Central customer-number, `balance`, `balance-due`, `credit-limit`.
* BigCommerce orders in the window: id, date, status, total-including-tax, payment-status.
* Open Business Central invoices: invoice-number, due-date, remaining-amount, linked order id if any.
* One-line summary: total ordered, total outstanding, any order whose payment-status is paid but whose invoice is still open.

**Rules & Guidelines:**

* Tools whose names start with bigcommerce-  are on the bigcommerce server; tools whose names start with business-central-  are on the business-central server. Both must be connected.
* Read-only: do not call any `-add`, `-update`, `-delete`, `-create` tool on either server.

**Validation:**

* If balance-due is greater than credit-limit and credit-limit is above zero, flag it.
* Do not infer payment from order status alone; use payment-status for BigCommerce and remaining-amount for Business Central.