In 2010 I set up a 5 year payment plan with Discover to pay off $15,000 in debt. The card was closed and the payments were deducted each month automatically from my checking. Around Christmastime 2013 I was going to be short and contacted Discover to see if I could delay making a payment. I remember how easily they said 'no problem' and so basically I skipped a month and the payments resumed the following month. No fees, no hassle, nothing. I didn't think much about it and thought I was continuing on my way to getting my financial house in order. Then, as my payments were coming to a close in 2015 I realized that Discover had been reporting me as 30 days late for 15 straight months. I could have brought the account 'current' along the way if I had known that I was 30 days late, but didn't realize it. Any chance if I contact them they might remove a portion of those lates?
Any advice on how to approach them?
This is the only negative account still on my report, so I'm guessing that the 15 lates are having a significant impact.
BTW, I do have a current credit card with Discover now (not sure if that matters). 
Thanks in advance!
Just updating my original post.
A few days ago I emailed the CEO of Discover explaining the situation and asking if they would do a good-will adjustment to remove the late payments.
Today, I got a call back from someone in the executive offices. (They said they no longer show the account in their system.)
They said they have sent a request to the 4 credit reporting agencies that they report to asking them to remove the account.
So, I guess that's what I wanted, right? 
Somehow I guess I thought they were going to change the reporting from late to on-time. But I guess if it was a negative report then things should improve by it going away, right?