If you signed for a plan, then you are in serious grease, regardless of whether or not you have a copy in hand. Signing = admitting guilt. You will need to take what you have down to a family law attorney, now, to see what, if anything, can be done.
Hopefully you did not sign a safety plan. If you did, the case cannot be dropped and you could be headed for lots of problems. Whoever told you about dropping a DCFS case is either someone practicing law without a license or an attorney with very little knowledge of DCFS proceedings. Hire a lawyer who is experienced with DCFS cases and see what can be done to minimizew the damages.
I hope, for your own good, that you did not sign a safety plan. You should seek the advice of an attorney who has experience with DCFS to make sure you're not in a heap of mess.