I understand your confusion, when you got a prediction of "Will never finish" when all your work has already been completed. The most important thing you should note here is that this prediction is based on the trend that has been calculated for the burndown in the iteration.
I have played a little bit with our demo data (check attached screenshots) hoping that it will help explaining what the trend represents. The trend line is calculated based on algorithm that presumes that the team is working in a consistent manner. This means that if you have continuously added items to the iteration, the trend will assume that you will continue to add items in future. As you can see on the screenshots in the current moment all the work has been completed, but based on the past days activities the trend is still going up.
In order to avoid such situations, I will encourage you to add all (as much as possible) of your planned work in the beginning of the iteration. If you only complete tasks (or complete much more stories/tasks than the one you add in the iteration) the trend will be going down and the estimated completion date will be more accurate.
If you still feel that there is something wrong in your project and the presented data, please send us relevant screenshots that may help us identify the problem, if it exists.
Do not hesitate to contact us at any time if you have any further questions about TeamPulse.
the Telerik team