Our business customers pay their invoices through a portal on our website. Until last year, the credit control team sent reminders for overdue invoices by hand. Each morning they worked through a list, a few hundred customers a day, and a reminder went out whenever somebody reached that name.
We automated it, and the automation was an improvement in every way the team cared about. The billing system now selects overdue accounts, builds each reminder with the invoice attached and a link to pay, and sends them all in one run. The run was scheduled for nine o'clock on the third working day of the month, after statements had gone out, so that customers would read them at the start of their day.
On the first live run it sent about eleven thousand emails in under four minutes. Within a quarter of an hour, several thousand customers had clicked the link. The portal had been sized for the gentle traffic of the old manual process, and for twenty minutes it showed an error page to almost everybody. Customers who could not pay online rang the credit control team, who were now handling a morning of calls instead of a morning of reminders. A few paid twice after their first attempt appeared to fail.
The automation was correct. Each reminder was accurate and went to the right person. What we had removed without noticing was the pacing. The team working through a list by hand had been spreading demand across the whole day, and nobody had ever described that as part of the job.
The reminder run now sends in batches of five hundred every ten minutes from eight until midday, and the batch size is linked to the portal's response time, so the run slows down by itself if the portal starts to struggle. The portal scales up before the run starts. Payment pages now check for a payment already in progress on the same invoice, and the credit control team has a dashboard showing the run's progress, so they know what is coming.
Anything we automate that sends messages to people also sends those people to us. The size of the crowd is decided by how fast the messages go out.
– Serguey Shinder
