If you have a valid credit card on file and you know your pin number you can pay by dall'ing 611. You can also buy a voucher from select stores or even online at recharge.com and use that via self serve or via 611.
Could you be more detailed in your issue? The deactivation date in December is when you lose your account and number after the 90 day grace period of not paying. If your payment go through, but still didn't activate then you need to contact mods as stated above.
