Why have I received an email saying that my Premium subscription was cancelled if I was only using Free?

I received an email with reference number 79359368 saying that my Premium subscription was cancelled. 

According to our records I found you had a yearly subscription plan as of roughly a year ago that was cancelled for non-payment after the rebill attempted to charge you again and failed. 

This was the reason why you received that email about it.

 

Reference number     :79359368
Order Date           :09/04/2014 09:18 AM