I received a battery in a sealed box with a used Inspire 1 that would not charge the first time it was attempted.  The battery has been returned to the person I got it from - again this was in a sealed box.  It was immediately returned approximately 4 months ago to the supplier.  There has been word that it was reluctantly accepted to be replaced.  I am still waitiing!  What can I do?   I am now without a good battery, bad battery and the money to replace the battery.  

Hello sir, may I know your case number? if problem caused by product faulty, and within warranty period, we will help you deal with it, DOA or RMA, please do not worry about it. If you have sent it to retailer from whom you bought it, you could contact with him to check process as well.
You could check our after-sales policy on this website: http://www.dji.com/service/policy