Okay, when I give the wrong prelim on these plays, I'll give the coach an extra second's explanation if he seems like he wants one. "Coach, I had defensive foul all the way; I just signaled it wrong." He needs to accept this explanation and move on. If he doesn't, it's on him. Everyone does this now and then, especially early in your career. It gives you good practice dealing with coaches.
As for the line call, it's always a good idea to try to focus on not calling other lines, but it's a good idea in and of itself regardless of whether the coach was an arsehole about it all.