Depends what you mean by incorrectly. If you make a genuine mistake then that in theory could be corrected, but if you deliberately mislead in your application then you could receive a ban for a number of years , not necessarily forever, for misrepresentation.
Employing an agent is no guarantee of completing a correct application and in fact an agent could well make mistakes out of your control. At least if someone makes a mistake without an agent then they only have themselves to blame not the agent.