I don’t even have student loans so I know that this is a big scam. The actual number to call them back at was contained in the voicemail I got. It can be found at https://drive.google.com/file/d/1kpx8aCcEyOuOfaGJbCIQz92I8GwaSG_7/view?usp=drivesdk
The callback number is (202) 843-5999. The "agentv is 2561. The validation code is 070120.