Building manager agent in Brussels

Hello there.
Our office building in Brussels has been managed by the same agent for the last 30 years or more....and some owners are not happy about this. She uses an old system for invoicing owners which makes everything impossible to understand and identify costs, inefficient response and management of meetings, and always asking for offers to her "company" friends in Brussels. There is always soething to repair, and basically, it is not transparent at all....we do not understand why maintenance costs are so high, and would like to change this agent.

Can anybody recommend a good building manager agent in Brussels?
We are in great need of someone professional and if possible, young!!

Thanks