Pay back over payment on my settled account

After paying off many vehicles through Wesbank finance , I paid up account once again end of Jan 2020. A debit order went off on 1 Feb and I requested reimbur*****t by email.

Here is Wesbanks response-

Thank you for your email. Kindly confirm that the debit order will not return unapid and that it will not be reversed in order for us to assist with the request. We would like to take this opportunity to thank you for entrusting WesBank with your finances. Yours in service, Customer Service Centre ***.

www.wesbank.co.za Fax: *** Wesbank has my banking details , why not just repay me the payment they shouldn’t have received. Letter not signed and poorly written.

Come on Wesbank