In the first set of bubbles, the character comments that he said there was no need to come pick him up. He also adds that the have done this song and dance many times.
The character replies then that "I was shopping for dinner, so I dropped by"
However, I'm confused of what the character replies here here. Is こき使う used for oneself? "You are very motivated"? Or is it about the other character means to exploit him?