Dear Liz: Last year my mortgage was sold to another company. I didn’t know that I had a new loan number, so my automatic payments weren’t posted properly. With the help of my bank, I was able to sort this out but not before the new company reported me as delinquent to the credit bureaus. I have never been late with a payment in 15 years.

I pleaded with the company to remove the delinquency from my credit report, but they declined, saying their records show that they fulfilled their obligation by notifying me that they are my new lender. Do I have any recourse and what are my options in getting this delinquency removed from my credit report?

Answer: You can try disputing the delinquency with the credit bureaus, but that is a highly automated process. The company may check its records and respond to the bureaus as it did to you, refusing to remove the black mark. It’s worth a shot, but far from guaranteed.

You most likely will need to get to the right human being to help you. Sometimes when you run into a brick wall with customer service, you can turn things around by appealing to someone’s expertise. Asking the customer service rep, “If this happened to you, what would you do to fix it?” may get you pointed in the right direction.

Of course, you may have been talking to a call center worker with little training and even less authority. If that’s the case, ask to speak to the manager. You might also write a letter to the company’s chief executive, asking directly for help.

Another option is to involve regulators. Filing a complaint with the Consumer Financial Protection Bureau or your state attorney general may get results.

A single missed payment can knock more than 100 points off good credit scores, plunging you into the “average” category and causing you to pay more for such things as credit card interest, insurance and cellphone coverage. It may take considerable effort, but it’s worth fighting back.