If you pay with credit card, it usually just takes the money from your account monthly (IIRC on the day you subscribes, ie when your 2 week trial ended on the 13th of a month, you have to pay every 13th.).
But you can also send in cheques to HTC.
But whichever way you do it, you can cancel that payment at any point you want to. Youll be able to log untill the month you paid for runs out. Reactivating a 'sleeping' account *is* possible, youll have to mail HTC or call them. They need to reactivate it manyally. (You loose all perk point and squad affiliations doing that).
If you have any questions or troubles about billing, just send a mail to
billing@hitechcreations.com .
I hope that answer your questions?