Hello, I work with Django daily as a full time developer, and I will be able to find the problem with your app. Will require the source code, as well as a dump of the DB where I can replicate the issue.
If the problem is fundamental, e.g. it requires many hours to fix, we will need to discuss about additional milestones. I am happy to debug before the project is awarded, so I can tell you exactly how long it will take to fix.
Ioannis