Hello Mister N.,
1. Sorry, I could make it yesterday.
2. I got jammed somewhere.
3. Good luck on your exam.
4. Hope you let me or your parents down.
#1 and #4 sound a little odd, as the negative form would be more usual.
With #2, did you mean to say that e.g. you got stuck in traffic?
All the best,
Student or Learner