On Custom Workflow, default email address is being used as a responder!

Hi,

On our Custom approval workflows, when a user approves the expense through the mobile, the default email address is being used as a responder instead of company email address. It causes workflow error on our Oracle EBS system. Eventhough the user change the responder email adress before sending it, it always goes through AOL account.

For example, Notification mails go to the company mail address that has mlpcare.com extension like "xxxxx.xxx@mlpcare.com" and user approves it from that mail. User basically opens the mail and click on ACCEPT or DECLINE. But the problem occurs, if user's default mail address is other than