D I have to pay taxes on the $3750.00 if I have already paid taxes on this money? Will have to pay taxes on this again?

When I left my work my contract stated that if I left I would have to pay back $3750.00 on my advance that was already taxes.  They sold my book of business for $1066.00 and they put the remaining amount on line 7 on my 1099 misc form.  I claimed hardship so I didn't have to pay it back.  If I was already taxes on this, why am I being taxed again?