Scorekeeper error

[Scrapper1]

This did not happen in a match that I worked, but it was posed to me by a very senior official. Team A wins rally and asks the official scorer who is the correct server. The scorer tells the coach (and this is all heard by the R2) that #12 is the correct server. #12's service results in three points for Team A when the official scorer informs the R2 that she made a mistake and #12 is not the correct server.

How should this be resolved? I didn't have my rulebook with me, but I said that the fair thing to do is to cancel the 3 points, put Team A in the proper alignment and allow the correct server to serve for Team A.

I know the rules aren't always fair, but the senior official said I was correct. Anyone have a specific rule citation that covers this situation?