Who was Roman speaking with on the phone?

When he said "the money is yours, and continue the work"?

And how realistic is it that a law abiding citizen would shoot someone in the stomach, based on a stranger's say so, especially when that someone was a close relation???

Edit: So the season premiere claims he was talking to no one. It was a hallucination. Is that how hallucinations work? I didn't think so, but I'll admit I don't know much about about them, other than they're supposed to be visual, which this was not. Either way it was a horrible nonsensical cop out.