$99 for the year promo issues

[Kuss929]

Got a pop up about the $99 for the year promo. Could not do anything about it at that time. When I looked into it and tried to sign up payment keeps failing. Everything pointed to cancelling subscription and renewing it with promo. Problem is payment for Dec came out a week ago and my subscription does not end until Jan. That is when it will revert back to Spotify Free when I can then get a premium subscription however $99 promo ends Dec 31. There has to be a simple way to sort this out. 

Tim