I think that's a generic reply they send everyone. They don't actually read everyone's emails... they must be getting thousands everyday. But just to be courteous they write back to us even though it's completely irrelevant to the query/feedback 😛
It's frustrating though... your letter was really good! It deserves to get their attention! Maybe resend it? If you get the same response again, you know they're not actually reading it. But if you get a slightly different response with maybe an extra line or two from them, maybe someone did take notice.