A charity shop owner has been prosecuted, and three shops have closed down after they were caught breaking the rules.
The Charities Regulator said they investigated 11 stores in total - seven of which have now changed their names.
Since the body came into operation last year, 28 complaints have been received from members of the public.
Eamonn Timmons from the Charities Regulator said people should check to make sure the organisation is a registered charity.
"Check the public registry on charitiesregulatorauthority.ie and check to see if the organisation is a registered charity.
"If not, please contact us...and we'll take the concerns and review them from there."