Round 3 of disputes

Hi everyone! As you all may know I started to clean up my reports in July of this year. I started in July with a combined total of 23 negative items. Since then I have had 11 items removed myself. I have student loans that are listed several times for each lender that is why I have so many negatives. Now my question is... I have one student loan for $480 listed twice on my Experian report (it's only on Experian). The school is the one listing it (no other name). I called them (the school) after I disputed and it came back verified, they said one is most likely the loan and the other is a collection for the loan. Although they have different acct. #'s, the school is the one who is listing it both times. Actually they(the school) couldn't find one acct. # at all, they were basically guessing. So I went to the The National Student Loan Database that is online and printed out the loans I had. And of course I only had one for $480. So do you think I should call the school up and find out if it really is a collection and the original loan and have them put it in writing and then dispute as the account is listed twice (and send the proof with the dispute) or should I send Experian a copy of the Student Loan Database printout and say its being listed twice here's my proof? Am I right, the lender can only list the debt once? If it was under a different name(the school and then a collection agency) it could be listed once as a collection and once as the original loan, right? Am I screwed because they gave them different acct #'s? The lady I spoke to said they would have different account # if one was a collection. When I spoke to the school about this they wanted me to fax them a copy of my credit report with the entires on it. I was scared to send them my report because I thought it would help them verify, besides THEY should have that info. in their computers. After all they did verify the entries? Any advice would help, I'm running out of ideals and time to do the rest of my cleaning up. Thanks