Hold overdue FreshBooks clients out of your next Mailchimp send

**Objective:** Find FreshBooks clients whose invoices are overdue by more than `{overdue-days}` days (default 30) and report their Mailchimp subscription, so marketing can decide who to leave out of the next send.

**Step 1: Find overdue invoices (freshbooks server)**

Call `freshbooks-get-invoice` with `outstanding.min` 0.01 and `due-date.to` set to today minus the overdue days. Use `company` `{company}` if given. Group the results by `customer-id` and total the outstanding amount per client, by currency.

**Step 2: Get client emails (freshbooks server)**

For each `customer-id` call `freshbooks-get-client` with `id` set to it. Keep `email`, `organization` and name. Clients with no email go in a separate list.

**Step 3: Look them up in Mailchimp (mailchimp server)**

For each email call `mailchimp-get-list-member` with `email` set to it. Record each list, `status` and `tags`. Emails with no result are not on any list.

**Step 4: Report**

Two tables. First, overdue clients who are subscribed, with list, tags and overdue total: these are the ones to hold back. Second, overdue clients who are not subscribed or not on any list. Add a count of clients with no email.

**Rules & Guidelines:**

* `freshbooks-get-invoice` and `freshbooks-get-client` are on the freshbooks server. `mailchimp-get-list-member` is on the mailchimp server.
* Do not change tags, segments or subscriptions. Recommending an exclusion is the output.
* Read-only. Do not call any add, update or delete tool on either server.

**Validation:**

* If no invoices are overdue, report that and stop.
* Match on email only, case-insensitive.