How do I track bill payments and follow up with my customers?

The Simple ERP module allows you to obtain the list of unpaid invoices, and to dun your customers.

1) Upon receipt of payment of an invoice, open the invoice interaction.
In the "Invoice tracking" field, choose "Invoice Sale - 04 - Total Payment", then Save the interaction.

2) To follow up, go to the module Simple ERP / Invoices (menu up -> Simple ERP,
then menu up -> Invoice).

At the top of the invoice list, click on the "List of unpaid invoices" button.

You get a list of unpaid invoices. Click on each interaction to restart the client.