Our house plans show quoins at each corner of the house which we thought would be part of the brickwork. We didn't realize the builder would just cut styrofoam sheets and glue to exterior brick, then finish with a stucco paint. It looks awful! The quoins are uneven and there is stucco paint on the bricks. We have tried to get it fixed, but to no avail. How can we remove the quoins and clean the mess off the brick? The brick is a light grey color, the stucco is dark grey.