Medicare Overpayment

Hello,

I received a letter from Medicare stating that they have made an overpayment and are asking for refund. The reason they mentioned for overpayment is the claim was submitted with incorrect information concerning the number of services or entry of charges. Therefore payment was made to you in error. When I find all the entries of overpayment, i came to know that most of the cases were for CPT® 99202, 99203, & 99204.

Can anyone suggest me what action should be taken in this case.