Help with a partner

[Reffing Rev.]

Last night I worked with a new partner for the first time. He said he's been doing sb for 8 years, I have my doubts. Here is play situation:

Runner on 1st, no outs.
Batter hits a nubber down the 1B line. In our pregame he asked if I wanted any help on the ball in the dirt in front of the catcher and any "secret signals" to indicate catch no catch etc. I am PU and glued in and see the ball the whole way into the pitcher's glove who picks it up and throws to first late. My partner comes in from behind 2B calling time to talk to me. (I know something bad is about to happen) He tells me the ball hit the batter's foot out of the box. I told him I was sure it did not. He said "you were blocked out, I clearly saw it." I said, that I'm sure I saw the ball all the way (because I did - I was faster than the catcher most of the game) so lets let it go. We separated and I turned to head back to the plate and got two steps before I heard him say, "Batter is out on interference."

Question 1: What would you do at this point?

Immediately the hc who was 3b coach called time and came to me for clarification. I simply said, "Field umpire ruled interference, check with him."

Question 2: Is this "selling out my partner?" (he thought it was).

Question 3: What do you do post-game? (We had a few other difficulties so he shook my hand as we left the field and went towards a different parking lot.

Just seeking advice...