I JUST went through this about a month ago... sometimes it happens with consolidating your student loans. I got it fixed, but now on EQ and TU they aren't showing ANY of my student loans, so my debt dropped by $100, 000. I won't bug them about fixing that.
Get a copy of your credit report and put an asterisk next to the errors, add a cover letter explaining the situation, fax it, call someone two days later and they can have it fixed in about 48 hours.
I owe Sallie Mae $55, 000 in student loans, but they were reporting it twice (one at $49,000 and another at $55, 000) due to a consolidation error.
It can affect your credit when applying for mortgage because it makes you appear like you're in much more debt than you actually are.
But NOW, they're not reporting anything on two of my reports and I'm not happy about that either because the payment history was helping my credit out.
My head is hurting thinking about this.