I have a fully configured mantis bug tracker for tracking issues in apps that I create. When an user is disciplined and goes straight to mantis to write a issue report, he/she will have fastest response and everything regarding the issue will be very easy to track.
However, not everyone is keen to do so. They report their problems via phone, e-mail, don't report them at all.
What would be the best way to nudge them towards the using a bugtracker system? Clearly, they HAVE to see some immediate benefits so they can return and look for more benefits.
EDIT:
I am talking about support for the products that I sell as an ISV.