Billing errors are not handled well.

[marlowk]

Every time there is a billing error with my Spotify Premium renewal, all of my stored music gets deleted from my phone. This requires that I re-download all of my stored music, taking up quite a bit of time and using a lot of bandwidth. It would be really healpful if there were a grace-period for rectifying my credit card information before I have to go through all the trouble. Many of the billing errors are not my fault—for example, my card was cancelled after my number was stolen in the recent Target debacle, which coincided with my subscription renewal. And now I'm left re-downloading everthing yet again. I am very unhappy about this.

[Peter__]

If a payment fails Spotify normally do try again in a few days before reverting your account to Spotify free at which stage you loose offline content (since you don't hold a license for it). If you do get a new card though, you can update your payment details from your online account before your renewal is due which should stop things like this happening. 

[Marco]

I've moved your topic over in the help section, since, as Peter mentioned, Spotify already gives you this grace period. Peter also mentioned a few other important facts how you can avoid losing offline access - if you got any further questions please feel free to ask here. 😉

[marlowk]

The time between receiving a failed billing notification via email and the time when my account was downgraded to free was less than 24 hours. If there is such a several-day grace period, then my experience suggests that the system isn't executing it properly.