In the “Wisconsin State Journal,” this question and answer was given:
Question: What happens if the recount isn’t completed by then?
Answer: If the recount is certified by Dec. 13, the state’s results are guaranteed under federal law to direct which candidate electors vote for on Dec. 19. After Dec. 13, Congress could vote to choose which candidate gets Wisconsin’s votes, with the governor breaking any tie between the House and Senate.
I think the Congress will let Wisconsin’s original 10 electoral votes stand.
The Wisconsin State Journal failed to identify another option. If the vote cannot be certified on the 13th, the state legislature is empowered to appoint its own slate of electors (which could well be the Trump slate) in order to insure that the state's EVs are counted on the 19th.
Inasmuch as both houses of the Wisconsin legislature are Republican (as are Michigan's and Pennsylvania's), thee is no doubt that Trump will gain all 10 EVs.
GREAT!