Really need advice!

I have a situation I really could use some advice on -

My last exchange with N was a text from him telling me that he had used me for a reference. "Hope that was ok. Would love to hear your voice." I called him, we had a stilted conversation, and I told him it was fine. Next day, I emailed him and told him that maybe next time he should use someone else, perhaps someone whom he didn't owe money, and that to have a friendship you need to actually put something into it, etc. We had another brief email exchange following, where he said I couldn't possibly understand how busy he is, I told him I don't like being taken for granted. Blah blah blah. We didn't end on terrible terms, just tense.

Then I found this site, you folks, and put it all together. It's been 2.5 weeks NC and I have been feeling really good.

Here's the dilemma-
Last night I got a call from a number I didn't know. No message, so I checked early this morning. It's from a realtor in his area. I guess he and new supply are buying a house! Or SHE is, probably.
I am certain they will try to call again today. Do I:

- break NC with N and tell him to provide another reference?
- give a lukewarm, vague reference?
- go full tilt and tell the realtor that I wouldn't trust him with my last dime?
- something else?

I don't want to break NC, but I am not comfortable giving a good reference. But last we left it I hadn't told him to stay away, so I am concerned that if I blast him to the realtor there will be nasty repercussions. I'm mostly past the anger and revenge stage, and would prefer it all just be over. Maybe I just don't pick up the realtors' calls?

What do you think?