Openconcerto propose de faire des relances par mail mais je n'arrive pas à trouver les templates à modifier pour traduire le texte anglais :
Late Payment reminder
It has come to our attention that the following invoice has not been paid to this day.
Invoice # FACT2013-XXX from 10 April 2013 of XXX duedate 10 May 2013.
We assume that this is a mere oversight and we would appreciate it if you would settle this invoice as soon as possible. In the event that this has already been accomplished in the meantime, please ignore this notice.
Merci de votre aide,
Florian