A check marked paid in full and cashed will usually satisfy any further requirements. If you worry they will pursue this matter you may wish to sign an agreement where both of you sign acknowledging the matter is settled and you have fulfilled your obligation monetarily.If you call a local attorney they can draft this for you or you can write it out yourself. Another way to handle this is to pay the body shop directly once repairs are made if both parties agree to that and have the repair shop sign off that all damage from the fender bender has been taken care ofAs i said the paid in full may suffice but you may want to be extra cautious if you feel wary of this situation.