Identify two coincidences involving Compeyson. Why does Magwitch hate him?

Compeyson is the man who left Miss. Havisham waiting at the altar.

Compeyson (and Magwitch) serve time in jail for forgery. Compeyson received half the sentence Magwitch was given.

Magwitch hates him because Compeyson had him do all of the dirty work and shifted all the blame on him when they were caught.