Problems with credit reports are more common than most of us might think. In fact, it should make your nervous enough to review your own credit reports if you haven't done so recently. There are three different credit reporting bureaus and they will send you a full report once a year at no charge. Even if you have to pay for them though it is going to save you money in the overall scheme of things.
Sometimes these errors are the result of information not being reported correctly. For example you may have paid off a balance on an account but it is still being shown as something you owe. You may trade in a vehicle for a new one and then find out your credit report is showing two open accounts for auto loans instead of one.
Identity theft is a huge problem in our society, and one you need to carefully guard yourself against. Identifying accounts you didn't open on your credit reports is one of the main ways to find out this is taking place. Those lenders that look at your credit report though are going to assume they are your accounts until you get the situation resolved.
Don't assume that what is on your credit report from one reporting agency is the same as the other two either. In many instances the errors will be the same but if it is an in house data entry problem then it will only show up on one of them. That could be the one credit report though that your particular lender is looking at. The process for getting errors corrected can really drag out so make sure you get the ball rolling as soon as you can.
It is going to take time for you to go over all of this information. Carve out several hours to look at the accounts that are on each one. You need to verify they are yours, the balances are correct, the payment history is correct, and read any notes on the accounts. If you find mistakes or things you aren't familiar with make sure you mark them for further evaluation.
If you do indeed find errors, you need to gather as much information about the account as you can. This is the only way you are going to be successful with getting the issues resolved. You will need to submit the information to each of the three credit bureaus. Don't just send the information to one of them as you will continue to have issues with the wrong information on them.
Send each of the three credit bureaus a copy of the credit report, the letter you wrote, the dispute form, and the verifications. Make sure you keep a copy of everything for yourself too. Document when you mail them the information and any correspondence via certified mail so they can't say they didn't get it. Give them some time to review the information and to get back to you.
It is to your advantage to keep a close eye on your credit report. You should be able to apply for credit and not have to worry about what is going to come up. Yet too many people only discover there are errors on their credit report when they get turned down for a loan. It can be devastating to not get the home or the car you want due to these problems needing to be ironed out first.