Compare what a customer owes in Chargebee and Business Central

**Objective:** Produce a single receivables view for `{customer-email}` combining Chargebee dues and Business Central balances, and say whether the two agree.

**Step 1: Chargebee side**

Call `chargebee-get-customer` (Chargebee server) with `email` set to `{customer-email}`; stop if there is not exactly one result. Then call `chargebee-get-invoice` (Chargebee server) with `customer-id` set to that customer's `id` and `amount-due.min` set to 0.01. Add up `amount-due` and note the oldest `due-date` and any `dunning-status`.

**Step 2: Business Central side**

Call `business-central-get-customer` (Business Central server) with `email` set to `{customer-email}` and keep `customer-number`, `balance`, `balance-due`, `credit-limit` and `blocked`. If none is found, report "not in Business Central" and give the Chargebee figures only.

Call `business-central-get-posted-sales-invoice` (Business Central server) with `sell-to-customer-number` and `remaining-amount.min` set to 0.01 to list open invoices. Call `business-central-get-reminder` (Business Central server) with `customer-number` to list reminders and their `reminder-level`.

**Step 3: Report**

Show a two-column summary (Chargebee, Business Central): total outstanding, overdue amount, oldest due date, open invoice count, dunning or reminder level, credit limit and blocked flag. State the difference between the two outstanding totals and, if it is non-zero, list the invoices that appear on one side only.

**Rules & Guidelines:**

* `chargebee-get-customer` and `chargebee-get-invoice` are on the Chargebee server; the other Business Central tools named here are on the Business Central server.
* Read-only. Do not call any Business Central create or update tool.

**Validation:**

* If the two systems use different currencies, show both and do not subtract them.
* Treat a difference under 1.00 in the same currency as rounding.