Fantasy rules situation

[Karak567]

figured this could get its own thread

so one guy in my league is in dead last... he has a 0 % chance of making the playoffs - essentially he is done

he started cutting random good players from his team in an obvious attempt to torpedo the league and then he went on to tell me, personally, that he planned on cutting every good player he could from his team and replacing them with players from the DL. when i asked him if he was serious, he said yes

so i locked his team. this league was supposed to all be paid up front but i cut him some slack because he didn't have the money at the time - now he is refusing to pay even though he is mathematically eliminated from the playoffs because "i cant make the moves i want to make"

was i out of line in locking his team?