Maybe I was naive but I didn't consider that I would be charged for forwarding calls to the SpinVox voicemail system. Found this on their site after noticing the calls on my bill: http://www.spinvox.com/support_spin_my_vmail_pricing.html
Divert charges may be used by Carriers when you are diverting your calls to your Spin-my-Vmail voicemail number. Normally, these charges will come out of your inclusive minutes, if applicable to your tariff. If these charges are not being deducted from your bundled minutes, you should contact your Carrier to find out why.
Still a great service but you pay your operator for using it as well SpinVox for getting the messages.