The lawyers are working for pay. Beware of that.
Great point.
Seriously? Do you work for free? How about your mechanic or doctor?
Most of the advice thus far is what can be done long before you reach this stage. At this point you likely need a lawyer since no one is speaking to you, you allege there is a forged delivery signature and there is a significant about of money at risk. A lawyer can give you state specific advice of your rights and remedies at this stage of the transaction. There are usually time limitations for your remedies and you are spending valuable time looking for a "magic bullet" on the forum.