I have been through the same run-around that you describe since April 2006 regarding a phone I bought in Oct. 2005.
Just like you, I had become very discusted with the lack of service and the long wait time on the phone when trying to get to Inphonic. I finally contacted the CUSTOMER SERVICE dept. at my provider, Verizon Wireless. I once more recited my whole detailed story, complete with names, times, what was said etc. The rep. started to give me yet an excuse for a reason, why they couldn't do anything. I demanded to speak to a supervisor who could cut through the red tape. After much discussion it was finally agreed that Verizon Wireless would immediately credit my account with the $200 rebate I was owed. THEY ACTUALLY DID THIS! I dont know if they ever got their money from Inphonic but don't care either. Good luck to you.