How did you pay it?  Did you send a check with a 1040V voucher?  Or with a 1040ES slip?  Or pay online?   Send the IRS a copy of your check or bank statement or credit card showing the payment.  Maybe it got applied to the wrong year.

What did the bill/letter say?  It could be an additional amount.  

Thanks for the reply.  I paid online and funds cleared my bank account.  The amount they are billing is the exact amount I owed and paid. Also the statement does not mention anything about adjusted amounts.  The is also no letter of explanation. It is simply a bill statement.  Thanks

Just send the IRS proof of payment.

I would assume if you paid the IRS directly at www.irs.gov/payments, that you printed your receipt. If so, it's just a matter of sending them a copy of that receipt. Also, check your receipt to confirm that you actually paid your 2021 tax liability, and not something else. For example, if you selected 1040-ES, that would have been an estimated payment for 2022, and nothing applied to your 2021 tax liability.

@thi2day-gmail-co 

"the exact amount estimated by turbo tax "

The "amount you owe" calculated by TurboTax is not an estimate.