Android galaxy S5 phone calling different contacts than the one I selected?

[AC Question]

Today I tried to call a number in my contacts that is a landline. The correct contact was shown on my phone's screen but the voicemail of one of my friend's answered on the other end. I checked and the contact that I selected was not for the person that I heard the voicemail of. My friend called me back shortly after, which I had to apologize for calling early in the morning (because my phone chose to call her instead of the contact that was selected and shown on the screen).