The builders have made a real botch of the bottom 2 stairs on a staircase they installed, as the attached photo's show. This happened because the staircase they ordered was too short and didn't reach the wall at the bottom, leaving an awkward gap. They told us that it would be an easy fix to extend the bottom 2 stairs and risers to fill this gap and that we wouldn't even notice! The carpentry they employed to do this was poor and these stairs, which they knew won't be carpeted look dreadful. My question is can we replace these 2 stair treads and risers, so that they're like the rest of the staircase and if so how? Other suggestions of course welcomed too. Thank you all!