桃乐西

I received a letter from Canada Revenue Agency yesterday. it says that I am not eligible for the GST?HST credit for July 2006 to April 2007 because I am not living in Canada during that period. Therefore the government wants me to pay back the money $232.00 with an enclosed check.
I am now in china, how can I do with this? I don't know why they ask me to pay back money, because I didn't receive any tax return for 2006....

pls tell me how to deal with it, thanks a lot......