Double charged me for SIX YEARS AND TEN MONTHS

[jovenile]

Since January of 2017, Spotify has been double-charging me. I did not realize this until recently, when an issue with a lost credit card revealed two different charges to, essentially, two different accounts—one of which was created via Facebook, and one via email address.

However, the email address for my Spotify login is the same as the one for Facebook, and both 'accounts' are the same. Logging in via Facebook presents the same information as logging in via email. In fact, I am unable to log into the 'Facebook' Spotify account. For some reason, there is no warning, notification, or failsafe on Spotify's end to prevent a double-account being created with the same email. 

Thus, for six years and ten months, I have been charged an additional 9.99 CAD every month. The compensation I'm being offered by customer service is a refund for the last 12 transactions "as a one time courtesy." 

Look, I like Spotify; I want to keep using it. But I'm not willing to have paid an extra 800-something dollars to have used it. I'm hoping there's a Spotify agent who can help me achieve something closer to a fair solution.