I purchased 3 months for €0.99 on Wednesday 17th May and my account was debited but I am still only a free user. I logged out and in multiple times.
In it, it shows the Spotify username you paid for:
Logout of the app, and be sure to use it, instead of your email address, to login to your account. It's the one with the Premium features.
If you didn't get any email receipt, sometimes the amount gets 'on hold' even if the charge doesn't go through. Normally the amount gets back to your bank account a day or two later.
Hope it helps. :)