What does it mean when a guy expects you to answer your phone but he doesnt answer his?

you ever dated someone like this.he acts like hes busy like so busy he cant answer when i call him almost 60% of the time some weeks its worse than that but he expects me to answer his calls 100% of the time its quite annoying to me sometimes what i do is pretend to be really busy when he calls me and when i do decide to answer oh boy to him i was with every dude made to mankind whats really this guy problem