In 'Edit data' on the debtorsheet, you can change the debtor related information.
When making changes to this data, the data gets saved until the next import of information (synchronization with you accountancy software).
There are two ways to avoid this:
1. Change the data in your master data, the correct data will automatically flow to iController
2. Contact support to configure what the import overwrites. E.g.: when choosing not to automatically overwrite the email address/telephone number/language, you can use iController as the main source for this kind of CRM-data