Invoice Collection Automation: Saving 60 Hours Monthly for a Construction Company

The Challenge

Core & Saw runs their field service operations through Service Fusion. They process over 5,000 invoices through the platform. And their accountant was spending roughly 60 hours a month on one thing: chasing unpaid invoices.

Here’s why it took so long. Service Fusion stores invoices, jobs, and clients in separate database tables — and there’s no direct link between an invoice and the client who owes it. To figure out who owes money on invoice #4782, the accountant had to look up the invoice, find which job it was attached to, then look up which client was tied to that job. Every. Single. Time.

For each follow-up email, that manual lookup ate about 15 minutes. Find the invoice, trace it to the client, pull the job details, write the email with the right amounts and reference numbers, send it. With thousands of invoices outstanding at any point, there was no good way to prioritize who to call first. No aging dashboard. No automated reminders. No record of who’d already been contacted. Some overdue invoices just fell through the cracks.

The Solution

I built three n8n automations that solve the invoice-to-client mapping problem in code and handle the collection workflow automatically:

Automation 1: Data Pipeline (Service Fusion → Smartsheet). Pulls invoice data from Service Fusion’s API, programmatically traces through the Jobs table to connect each invoice to its client, and writes the enriched data to Smartsheet. This gives Core & Saw the direct invoice-to-client link that Service Fusion doesn’t provide natively.

Automation 2: Collection Workflow (Service Fusion → ClickUp). Creates a ClickUp task for each overdue invoice, pre-loaded with client contact info, the invoice amount, job details, and how many days it’s been outstanding. Seven email templates handle the full escalation sequence, from a friendly “just checking in” to a formal final notice. All the fields get auto-populated.

Automation 3: Sync Engine. Runs every 30 minutes. When a payment hits Service Fusion, the matching Smartsheet row and ClickUp task update on their own.

The Implementation

The hardest part was building a reliable bridge between Service Fusion’s disconnected tables. I wrote custom code nodes in n8n that query the API in sequence — first pulling open invoices, then batch-querying the Jobs table for each one, then resolving the client record attached to each job.

I worked with the accountant to design the seven email templates. She knew the tone the company wanted and how quickly to escalate. Each template fills in the job name, location, invoice ID, amount owed, and days overdue automatically. Now she reviews the pre-filled email in ClickUp and clicks send. That’s it. What used to take 15 minutes takes under a minute.

One design choice I’m glad I made early: the integration is read-only on the Service Fusion side. Data flows out of Service Fusion but nothing writes back in. Service Fusion stays the single source of truth for all financial records. Smartsheet and ClickUp are just operational layers for tracking and follow-ups.

The sync engine also handles the edge cases that trip up simpler integrations — partial payments, credit memos, voided invoices. And it only processes records that changed since the last cycle, so it doesn’t hammer the API or run into rate limits.

The Results

We went live two weeks after the initial discovery call. The difference was obvious immediately:

• 60 hours a month of manual work gone — the entire invoice tracking and follow-up process runs through the system now
• Follow-up emails take under a minute instead of 15 minutes, because there’s no more hunting through Service Fusion for client details
• 7 templates keep the messaging consistent and professional across the whole collection cycle
• Sync runs every 30 minutes, so the dashboard always shows current payment status
• For the first time, management has actual visibility into collections — aging breakdowns, follow-up rates, which clients are chronic late payers
• Every overdue invoice gets followed up on schedule, not whenever someone remembers

The accountant now spends her time on exception handling and financial strategy instead of copying data between screens. The system runs nights, weekends, holidays. It doesn’t forget.