What if the insurance adjuster tells you that if you don't settle in 30 days they will close their file?
A common strategy with insurance adjusters is to try to pressure people in settling personal injury claims fast, and for less money than they may be entitled to. This isn't necessarily because the adjusters are bad people, but the insurance company's profits come from paying out as little as possible on claims. Telling someone that if they don't settle in X number of days that the file will be closed is just a tactic to get you to hurry into such a settlement.
Under South Carolina law you have three years from the date of an accident to settle your car accident case (cases involving government vehicles have a shorter period). Whether or not the adjuster has "closed his file" is meaningless toward your rights. Hearing a comment like that should be considered to be a red flag that the adjuster is looking to possibly take advantage of you and your situation.