Over estimated earnings for 08-09, Missed out on tax credits

buba_2

Me & my husband are self employed, and claim tax credits, but have to put in estimates of income because we are self employed, our accounts for 07-08 where very good so we couldn't claim much and we based our estimate for 08-09 on the previous years figure,
but we have just had our accounts for 08-09 from our accountant and they are a LOT less due to a bookkeeping error from 07-08 ( It turned out not to be such a good year as we were told:mad:)
I contacted the tax credit people to tell them the actual figure for 08-09 and they have sent me a letter today saying its to late as the deadline was July 2009!!!

Just wondered if this is right and I have lost a chunk of money that i was entitled to?????