There are two ways you can dispute these. The way you should do it will depend on your desired outcome. First, if you have any intention of possibly filing a lawsuit against them for FCRA violations, you MUST first dispute through the credit bureaus. This is the route I tend to take first as well, because you never know how they will respond to a dispute and the ability to file suit provides leverage if you can prove that they know they are in the wrong. In your case, you have a letter from them telling you that they will delete your lates. Then, they did. So you can at the very least make an argument that the act of putting them back on after deletion shows intent. Whether that argument would be successful or not, time will tell.
I would file disputes with the CRAs directly. Let them be made aware of the issue that way, and if they choose not to correct their errors, you would then be able to apply leverage in the form of an ITS letter, or maybe even actually file a suit and possibly recover damages from them.
The second way is to contact them directly, as you mentioned. However, the problem I find when contacting a creditor directly is that you usually end up talking to a low-level employee who not only has no idea what's what, but has no authority to make any changes even if they did understand that their company made errors. It often ends up being a frustrating waste of your time. For example, years ago I had a mortgage dispute, with HSBC. I spent FOREVER on phone calls trying to get their errors sorted out. On one phone call, I called their collections department (returning a phone call), who then transferred me to their account management department, who transferred me to customer service, who transferred me BACK to collections, etc etc. No one had any idea what to do to handle my questions. It was so bad that their collections people would leave voicemails....and then when I returned the call, the same collections department that left a message now had no idea why I was called in the first place, because their computer showed that I had made the payments on time. A total mess. Naturally, some companies are better than others....and some are worse. Experience shows me that if I have to dispute, I go to the CRAs first for something like this.
