Disputing a legitimate debt will only hurt your score when it updates. In this case, even if they corrected the date all it would do is extend or shorten the time it's on your reports respectively by 1 month while dinging your scores for a recently reported derogatory. If you want it corrected, reach out to the reporter to have it fixed. If your goal was to get it removed due to inaccuracy, that doesn't happen as often as people make it seem. Typically there would need to be a chain of change in ownership where there's a high likelihood that proof of debt is not available or it's a company that is not likely to update. In the case of OCs, they almost always respond.
When you get down to it. The 30 day you were questioning isnt the main problem. The status of CO is whats hurting the most. Time to work out a settlement or PIF. Once thats completed then it will quit updating. The balance will reflect $0 and that wont count any longer against your util %'s. Then in time it will fall off.
