Step mom? Am I a b for this??

Long story short my ex’s daughter puppy died it got ran over yesterday and he called me today asking if I could pick her up I said no because I am currently working & usually get off work exhausted he called me a b & said that he would’ve never treated my son like this.. He always does this!! He will call me & get upset with me because of his daughter like her mom recently went to Miami for vacation & left her with her grandparents & Im not seeing him talk sh*t to her.. we have a son & RECENTLY broke up