That states your Vodafone Premium will last until Feb 26, 2018. Which I guess is correct.
If you're still getting charged, it probably means you're paying a different account. You should fill out the contact form, and someone from Spotify will be happy to help you within 24 hrs. Don't forget to check your spam folder for responses as they may end up there.
If you get an automated email directing you to the community or help pages, you need to reply directly to that email (even if its from no-reply) and one of the customer services agents will get back to you.