I have to say this is the positively the most frustrating part of the immigration process that I have been through yet. I think there's absolutely no reason it should take this long to get a background check for immigration.
I have known people who needed to get background checks from the FBI for work purposes (in the US) and it took DAYS, a week and a half at most. Why should it take so long for immigration??
And then, when you call the "customer service" hotline, they are so totally apathetic and unhelpful that it amazes me that they even bother with customer service number! They almost seem to have an attitude that they can't believe you would try to call them and ask them, how dare you? Even if you can't tell me much, it would be comforting to know you GOT my request, that my fingerprints were ok, and you are processing! But, according to them, I have to wait ten weeks before they will even acknowledge they received my request. Which is funny because most of the people on here seemed to have gotten their letters back before ten weeks even lapses!!
It's been seven weeks since I mailed off my request, I live about a three hour drive from the place you mail it to. All I can do is hope it comes soon. I had to vent my frustration with people who would understand.