Those WOF spins aren't related to the premium membership benefits. Freebitco premium membership benefits are broken for all the users since last few months. I had also received 10 WOF spins like that on my account. I don't have any FUN tokens on my account. Some people have also said that they received this type of email from Freebitco recently.

I did not get those spins, just checked the mail and there was no mail with 10 free spins. Looking at those issues with appearing / disappearing free spins I wonder what they think about their service? Are they aware that they need to have consistent service to attract people?
Even at that, I think that meeting that free 10 spins for Ling time inactive players still requires that the gambler meet up with some amount of BTC wagering and that is an extra task that could pause some limitations to your ability to meet that 10 free spins.
From the email, it seems that they are only sending selected gamblers that email.