Student loan relief company. If you return the call you can be removed from list easily.

Interesting post.
You claim the call was from a "Student loan relief company"
but, you also say "don't know" for the company name, and you gave us no way to identify the company to validate your claim.

Legitimate companies identify themselves.
Legitimate companies do not cold-call people on the DNC list
Illegitimate companies do not remove folks from their calling list merely because the called person called back.