Beg your pardon?
If I understand, two of your players warmed up pre-match with two of their players, and now their captain insists that those four players must contest the match?
No. Heck, even if the line-up is exchanged and the players erroneously warm up on the wrong court, you could and should fix that provided the match hasn't started yet.
-- Random Error Generator, Version 4.0
-- Master Moonballer