Based on the provided information, it appears that the caller is likely a scammer attempting to deceive the recipient into believing they are from Discover, a well-known financial institution. The mention of a code for a deposit application and the sheer volume of text messages sent (5 in one day) suggests a sense of urgency and potential phishing attempt. The fact that the recipient is certain it is not actually Discover implies that the caller is using spoofing tactics to gain the recipient's trust.
They claim to be from Discover, sending me a code for a deposit application, but its not legite, they have sent me 5 text messages alredy today