Build a dashboard that eliminates a lot of manual work

I am looking for someone very good with Excel to help me build a dashboard. In its current shape and form we coordinate with a lot of people, many of whom do not send correct data, leave data incomplete and do not update us of any changes they make in the dashboard resulting in us having to check every row of data as we do not have any process that can automatically check this and warn them. This is time-consuming and requires a lot of manual work that can (and should) be eliminated. We coordinate with roughly 15-17 people to collate data and they cannot be privy to each other's information so we also need that privacy maintained. From the data they send us, we prepare a dashboard using lots of Excel formulae and want to simplify and automate that as much as possible. We would also like data stored in such a way that we can just filter on year/quarter/month and see the data for that time period. The data we are referring to is various types of attrition, recruitment tracker changes, headcount data, manpower cost etc. of four regions around the world. We need someone with a very deep understanding of Excel (as currently we are not using any other system) and the ability to simplify data in a logical way.