You can verify recurring gifts by selecting Fundraising > Donation Management, then click the Sustaining Gifts tab and search for the constituent. You can also quickly determine this by examining the confirmation code associated with the transaction by using this article.

If you were able to confirm that it was a one-time gift, then you will need to contact your payment processor to discuss changing the verbiage that is being sent to the constituent's bank. If you aren't sure who your payment processor is, then please contact support.