Casual relationship gone wrong??

So I started seeing someone who I had a little casual relationship with before, but ended it because I wanted to have a real relationship, which I just got out of after 4 years. So I started to see him again and we had sex 4 times in the past month. Well now all of a sudden the last week he hasn’t texted me once. He was supposed to come over yesterday morning but never showed. When I tried to text him it sent as a regular text and not an iMessage. I tried to call him and it went straight to voicemail. I googled it and it says for iPhones if someone blocks you, it wont send iMessages but a regular text and the call will go straight to voicemail. I didn’t blow his phone up or anything since last Tuesday that I saw him. I texted him Monday and no reply, so when I called Tuesday all that happened. He is a super busy business man but I’m 99.99% sure he has blocked me. I can’t understand why. If he didn’t want to mess with me, then why did he? Why would he tell me that He would take me away for his business trips so we could have a little fun and take me on road-trips?? Ugh. I don’t have feelings, I’m just trying to understand. Should I give him the benefit of the doubt? Do you think there is someone else?? He told me his personal life comes last. Help!!