Checking your credit report at least once a year – even if you don’t use credit cards or have any loans – can help you correct any mistakes that could be hurting your credit score.

Every entry on your credit report will affect your credit score in some way, and many creditors do make the mistake of sending a duplicate entry on certain accounts. These duplicate “negatives” can have a very big impact on your credit score and might even prevent you from getting a loan.

Here’s what you need to do when you discover this type of mistake:

#1: Prepare a Dispute Letter

You will need to create a dispute letter that includes information about the creditor, the account number, the balance that has been inaccurately reported, and all of your personal information.

Make sure you double check this for accuracy, and can confirm that the entry is in fact, a duplicate. Start by asking the company that reported the information twice, if they will remove the erroneous second listing with the credit bureaus.

If one of your accounts went to a collections agency, both the original creditor and the collection agency may have reported your account. The credit bureaus will not consider this a duplicate entry, but you can check to make sure that the account has been marked as “paid” when it has been brought current.

#2: Contact all of the Credit Bureaus

You will need to contact each of the credit bureaus – Experian, TransUnion and Equifax – independently to report the error.

Send a copy of your dispute letter to each one via return receipt mail, and keep a copy for your records. The credit bureaus have 30 days to investigate your claim and will send you a copy of your updated credit report once the item has been removed.

#3: Verify that the Duplicate Entry Has Been Removed

If the credit bureau has not responded within 30 days, they may not have been able to remove the duplicate entry.

You will need to again contact the creditor directly to have them contact the credit bureau and ensure that everything is accurate and up to date. This can take some time, so be prepared to make a phone call and write a letter to follow up.

Keep records of all communications so that you have proof that you took steps to make the corrections.

Making sure your credit report is up-to-date and accurate can put you in a better position to get a loan or financing you need in the near future. But the burden is on you to dispute any errors in writing and follow up within a few weeks to make sure credit-report mistakes have been corrected.