How to hint i am mad at him?

So my boyfriend and I have busy schedules so it is hard for us to see eachother. But we never talk on the phone or skype anymore because he always has a reason he cant. He also just stops answerin during a conversation over texts, or says brb going for a jog (something like that) and then doesnt say anything for hours. How do I hint to him that I am kind of mad at him/ kind of pissed off? I am also leaving in 2days for 3weeks and we havent seen each other in about a week or two.