I think Canada Revenue made a mistake? GST/HST Account question?

When I did my taxes, it said I'd get $990.06 back. I got $817.11 back with an explanation that the remaining $172.95 was taken and applied to a balance I owe on my GST/HST credit account. Isn't that something that businesses have? I don't own a business, so what are they talking about? Is it possible they made a mistake? I don't owe anyone anything and the only government related bill I have is for BC Medical Services, which I pay on time every month...I'm confused!