I am attempting to cancel Spotify Premium and I've also run into this problem. I came in via Facebook and there's no password field in the Spotify app access panel on FB, and using my Facebook password does not work. Pretty lousy setup, IMO. It's like you're trapped in a loop with no way to cancel. Anyone know of a workaround?
I'm not sure the same thing will work for both of you - this is more likely to work for evangmm, but it may work for both of you. First, try completely logging out of both the Spotify website, and Facebook. Once logged out of both, try to log into the Spotify website again. If your Spotify account is connected to Facebook, it should prompt you to log in to Facebook. If for some reason that does not work, others have also had some success trying another browser (e.g. Mozilla Firefox, Google Chrome, etc). If you are able to download and try a different browser, that may help you out.
Hopefully these solutions will work for at least one of you. If they do not, your best bet will be to contact Spotify directly by clicking "About Us" at the top of the page, and then selecting "Contact Form."