Was I wrong or being mean?

Ok. Last night I called my guyfriend and I heard him pick up but he didn't answer it sound like he was fidgeting with the phone and heard him press a on and I kept saying hello. So I called backed and his phone rung 2x's and went to his vm. So I called him today while he was @ work. I asked him why he sent my call to vm. He said that he didn't and in some areas he don't get a signal. I told him when I called him the 1st he answered and I kept saying hello. The 2nd time it rung 2x's and went to your vm. He kept telling me that it was the area that he was working in and he wasnt getting good reception. Anyway he was at work so he said that'll he call me right back which he did. Well I asked him again and he said again that it was bad reception. I asked him why he's lying and he said he wasn't. So anyway he got frustrated with me and I was like I got to go bye. My thing is if he's telling the truth, why is he upset? Also, he knows about my past and I'm leary of what people tell.