Question

I was hired to watch over workers.
The arrangement was clear: we start at 6:50.
In actual practice (this is accepted among guards), when the workers notify that they have arrived or are just about to arrive, the guard leaves his home and comes to the checkpoint to let them in to their work. If they don’t call, then usually after a few minutes the guard himself calls to find out where they are, when they’ll come, etc.
Because there’s no point in wasting precious morning time (I need to help at home with the children, send them off to school, prayer, etc.) by waiting for nothing.
That’s how things were conducted for a certain period.
After some time I finished my shifts with the employer.
But a few days later the employer was again looking for a guard and advertised that he was looking for someone from 7:00.
I contacted him and agreed to come for one day (which I had free).
We didn’t discuss the time at all, and I was glad that it was from 7:00 and not from 6:50, as he explicitly advertised. Accordingly, I set my alarm clock 10 minutes later.
(It should be noted that a normal shift, and the accepted practice in our area, is from 7:00, and if someone wants earlier he has to make that known.)
I sat in my house from 7:00 and waited for a call from the workers.
After a few minutes, when the call hadn’t come, I tried contacting them; at first there was no answer at all (both from the workers and from the employer), but after a few minutes they called: “Come, we’re waiting.”
I came and let them in to their work.
If you come early there’s no line (relatively speaking) and they get in pretty smoothly, but from 7:00 onward a line starts, and whoever is late gets delayed twofold—roughly like driving to Tel Aviv in the morning during rush hour; every minute late equals a penalty of several more minutes in traffic.)
 
I feel 100% in the right because: a. It was 7:00 and not 6:50—that’s what he published for the new guard duty, and also when we spoke and agreed orally he didn’t say 6:50. (That’s why I set the alarm.)
b. At 7:00 I didn’t get a call. A few minutes later I called and they didn’t answer; when they did call, I left my house and let them in (subject to the line at the entrance).
The employer feels he was cheated.
Because:
a. He claims that already during the previous period of guarding he didn’t know that I wasn’t showing up at 6:50 but rather according to a call from the workers, and that sometimes I was “gaining” a few minutes. And maybe he deserves some compensation for that.
As for the fact that this is accepted and reasonable in the field—either he doesn’t know that, or he thinks it isn’t fair.
b. Regarding 6:50 or 7:00:
It is agreed that he wrote 7:00 and not 6:50, and also that he didn’t tell me it was 6:50 and not 7:00, even though it explicitly said 7:00.
But I should have understood it from the fact that that’s how we had worked before. That’s just how he operates.
Meaning, for him 7:00 means 6:50.
And there is logic to starting a few minutes earlier to save the wait in line, etc.
And in general he doesn’t even believe me that the night before I set the alarm 10 minutes later because in good faith I thought 7:00 means 7:00 and not 6:50.
 
c. The fact that I didn’t show up at 7:00 and wait there for the phone call is also not okay, because we agreed on 7:00 and didn’t agree to wait for a phone call. (And as above, he either doesn’t know this is a common practice, or doesn’t recognize the legitimacy of this practice, and also didn’t know that this is how I actually behaved with him during the previous guarding period.)
d. The fact that in the past the guarding was often according to a phone call and not according to exactly 6:50 was, as I understand it, because that’s the practice with him (not exactly—with everyone—but that’s how he presents it). If so, why didn’t I also understand, from my side, that even when he writes 7:00, and even though afterward he doesn’t say otherwise orally, he means 6:50?
As he sees it, it’s a kind of “whichever way you look at it”: if we go by what’s written, then it says 7:00 and at 7:00 I didn’t show up.
And if we go by the practice (which permits waiting until being called by phone), then the practice with him is 6:50 even though it says 7:00, and I should have been on standby (for a call) from 6:50 and not from 7:00.
e. Even if I’m right in the end on every detail, I still have to apologize because somehow, overall, I’m not okay.
I feel this is unnecessary hair-splitting and unfair.
6:50 is not 7:00, and there’s no claim against me—I acted fairly and in good faith.
And as for waiting for the phone call, there’s logic to it, it’s a kind of accepted custom, and it was the actual practice with him too (even though he claims he didn’t know that).
 
Who is in the right?
It should be noted that the pay for a day of guarding is 400 NIS, and he claims that damage was caused by the lateness in an amount even greater than a day’s wages.
He is also an upright and God-fearing person, but it is clear that he thinks he is 100% right, while I also feel 100% right.
 
What should I do?