1. How to change the user login credentials for the Salesforce integration connected to Chargebee?
2. The employee who connected Salesforce to our Chargebee account had left the organization, we would like to connect it with new credentials, how to update it?
When you would like to switch the user who has connected Chargebee and Salesforce integration you can make use of this article to reconnect with the new user. In case you have any specific duplication rules applied, and you do not want to apply these duplication rules to Chargebee integration-based create/update actions, you can create a user account that is only used for this purpose in Salesforce and use those credentials while connecting to Salesforce.
Take a backup of the settings by navigating to Settings->Third party integrations->Salesforce->Manage preferences. This is a precautionary step.
Ensure ‘new user' permissions are identical to the 'old user’.
Disable the auto sync in Salesforce>Chargebee Settings>Sync Health>Sync Settings.
'New user' should enable the auto sync again.
After the above steps are complete, test this by creating a test customer in Chargebee and do a sync to Salesforce. You will see a contact created in Salesforce with the new user's Alias Name (Alias name of that user in Salesforce).