"3‘it's pretty hard to come to terms with Angela's shabby treatment of Rick’
contemptible, despicable, dishonourable, disreputable, discreditable, mean, mean-spirited, base, low, dirty, shameful, sorry, ignoble, unfair, unworthy, ungenerous, unkind, ungentlemanly, cheap, shoddy, unpleasant, nasty
informal rotten, low-down, hateful
British informal beastly
vulgar slang shitty"
The above is from the Oxford dictionary.
The meanings which fit the context in question would be "contemptible" or the informal "rotten".