HELP! GST re-evaluation after reporting change in marital status to CRA

Help! I am completely confused by this.

A few months ago, I updated Canada Revenue of my change in marital status from single to married and indicated that my husband and I married in June 2008 (in India).

Today I got a letter from CRA saying that they have reviewed my entitlement for GST for July 2008 to April 2009 and that they are unable to determine if I am still entitled to the GST credit because they don't have "all of the necessary information". They want a letter that indicates my husband's net income for 2007 to determine if I am still eligible to keep the GST credit or if I have to repay it.

I just got off the phone with someone at CRA who was completely useless so I thought I would ask here. She just kept repeating the same thing like she was reading her answer out of a book. So frustrating.

Why do I have to show his 2007 net income?? We didn't marry until 2008 and he didn't come to Canada (as a PR) until the end of March 2009. He was living in India up to that point. We didn't even meet until July 2007, so what relevance is it what he made in 2007?? Do I simply write a letter stating what his income was or do I need some sort of documentation.

Any thoughts would be greatly appreciated!