Could not redeem code but easily resolved
I had trouble redeeming the code because of substituting the letter O for a number zero 0.  I did corrected my error and tried again with no luck.  I contacted Spotify support via the "contact us" on the web page.  (Note that I was a prior premium member, no longer active, but was signed on to that account).  THe contact us opened a chat session.  I wrote a description of the problem.  Someone responded me in a few minutes.  They ask to confirm that the account I was signed on with it the where the issue is.  They did some checking, then asked for me to type the code into the chat.  The checked again, I assume the reviewed both the code and what I have been typed in my redeem session.  The wrote back with the code in proper the form.  This to me looks like the corrected code I entered earlier.  I copied the code from the chat. I started a different browser so I could keep the chat going on the initial browser. Logged in, went back to the redeem page, pasted the code in from the chat and it worked.  All and all, this was a bit annoying but it was quick to resolve.
Rating: 5 stars