Accounts receivable tracking and collection system

We need an accounts receivable tracking and collection system. Currently we track unpaid invoices manually in spreadsheets: managers call debtors from memory, reminder letters are sent sporadically, and some overdue items simply fall through the cracks. Because of this money gets stuck for weeks and we learn about problems too late.

We need a solution that collects all issued invoices in one place, shows the debt amount for each counterparty and automatically calculates debt age with breakdown by period — current, up to 30, 30–60, 60–90 and over 90 days. The system should automatically send payment reminders on a configured schedule: gentle before the due date, more insistent as the debt ages, and record each contact in the invoice card. When a client names a payment date, the system records this promise to pay and reminds the agent to follow up if the money doesn't arrive.

We need workstations for collection agents: a queue of overdue invoices with risk priority, complete contact history, statuses and clear next steps for each debt. Management reports are mandatory — total receivables, average payment period, recovery rate — and exports for accounting. We require experience working with financial and accounting systems.