This is the Turbotax forum, we aren't equipped to answer credit score questions.
However, I can't think of any way to close a credit account other than paying off the balance and then contacting the individual lender to close it. There's no third-party or government site you can go to, you have to contact each lender.
Whether you should close an account is another matter. Sometimes, keeping unused accounts open is better for your credit score, assuming you can secure the account to stop yourself and others from mis-using it.