After 30 years of great credit, I missed a Lowe's bill that was routed to my junk mail. I had just forgotten my husband had used the card. I missed a single payment and the account went into delinquent status which I only knew about from another card that notified me my FICO had changed. This single incident dropped my FICO by over 150 points! This after hundreds of perfect on-time payments for every account I ever had; and right when we need to apply for a new mortgage. I composed a contrite letter requesting a goodwill adjustment to Synchrony and copied my FICO score history - didn't blame Synchrony at all. I also mentioned I'd been referred for treatment for mild congnitive function decline and stated what I was doing to prevent a recurrence by signing up for auto-pay. I used the saturation approached, mailing a hard copy to about 6 names I found by googling and also messaging through the internal account system. It only took 3 weeks, and they removed the notation of the delinquency and late payment. I'm back up to 813! I think it was most likely just the message I sent through their system- maybe someone with an aging parent or grandparent read it. I didn't get any replies from the hard copy letters. I'm sure if I'd had a longer history of credit troubles, this would not have gone so smoothly, but I was very lucky.
