None's dashboard

I purchased the US.GDP.2007Q4.NEGATIVE contract, which the exchange expired at 0 on Jan 31 15:49 after the BEA's "Advance" release. However, Reuters reports (http://www.reuters.com/article/compan...) that US final Q407 GDP was negative after BEA revisions (http://www.bea.gov/national/xls/gdpch...). I wrote to InTrade in February asking why the contract was expired at 0 after the "Advance" release and never received a response. I feel that the exchange violated its contract rules (which specifically tie the contract to the final number), and am disappointed and frustrated. How do I seek compensation?