As far as I see, the 24.95 / 19.95 amounts are only available at the Online Check payment option.
There, the 19.95 amount is for
automatically recurring payments only, as sort of an rebate for longtime members.
If you chose the monthly payment method of 24.95 last month, you should have been automatically billed the discounted 19.95 this month. That is, if you haven't canceled your membership.
If you don't like recurring payments, you could choose the 49.95 for 90 days. That's 16.65 per month - or paying for two and getting three months membership.
If this isn't the information you hoped for, I suggest you contact ccbill's support about a reactivation of your monthly payments (I don't know if that's even possible, though) or Chris at
info@ftvgirls.com to see what he can do. Both will probably need the old transaction details.