I write this as someone who has had the unfortunate experience of trying to cancel my subscription after getting Spotify premium.
Spotify themselves make it very, very difficult for you to cancel. It is an absolute nightmare. Some words of advice would be to not leave it to the last day or so before it runs out to try and cancel your subscription. You need to leave plenty of time to get it sorted before they take another £9.99 from your bank account.
I really wish I had read this forum BEFORE I had subscribed and seen the vast numbers of dissatisfied users unable to cancel....I would never have done it in the first place!
Don't be fooled into thinking you are inputting an incorrect password at the final hurdle when you are cancelling - you are not - they deliberately do this to make things awkward. You have to then fill in a contact form (which incidentally says could take 3 days to respond to - hence my earlier mention that you shouldn't leave it too late to start to cancel.)
Because it's not a direct debit, it can't be cancelled easily by your bank either. After speaking to my bank, the only way they could do it for me was to cancel my account and open a new one!
In the end, what worked for me was having to download a new internet browser and go through that. Luckily for me that worked, but I see from on here that that doesn't work for everyone.
I loved Spotify and was a big fan, and my cancellation was only going to be a temporary thing untill I had a bit more money. But now that's it. I'm done with Spotify for good. It's absolutely disgusting and to my mind is almost corporate theft what they are doing in making it virtually impossible to cancel.