i love these questions

in all fairness you should walk up to him like a man
and tell him to his face that he fucked up
then proceed to place your knuckles upon his face
after a good stomping you must give him a time limit to repay
or meet with further consequences

the key is to be 100% serious about your words
if he doubts you on ebit you wont get money back or respect

do not just let this go