Credit report bureaus are required by law to discuss your report with you if their report was used and you were denied or rejected credit when requesting a loan.
I have absolutely no idea what kind of help they can offer over the phone, so if you're aware, please post a comment here.
The TransUnion phone number to discuss your credit report (again, this is only available if you were denied credit in the past 60 days due to something in a TU credit report), is 1-800-663-9980. If you're in Quebec, you're special for some reason and should call this number instead: 1-877-713-3393
If you're looking for a FREE Trans Union credit report, follow my guide here, it's helpful and explains how to get a free report from the other Canadian credit bureau as well.