$12.50 or $1,250 it is your money and he owes you, and you are right it is the principal behind it! If someone asks me if they can borrow $5 then I EXPECT to get paid back, or I will come looking for you, why... be cause of the principal behind it all! However, if I GIVE you $5 then it is a gift.
Regardless of the amount a thief is a thief! Good luck Bro!