Who called from 3473528572

Msg said to avoid legal action, return call. If you do not return call, I wish you the best of luck in your future legal proceedings.

Claimed that legal allegation would be taken on me.

They can take a powder, too. I'm not sure allegations can be il-legal. At an educated guess this is the luck-wishing work of South Asian thugs making empty threats about phantom debts.

FTC alert: "Fake Debt Collectors"
http://www.consumer.ftc.gov/articles/0258-fake-debt-collectors

FTC blog: "Don’t recognize that debt? Here’s what to do."
http://www.consumer.ftc.gov/blog/dont-recognize-debt-heres-what-do