how you can cancel the auto billing without canceling the subscrition or the account

You need to cancel the subscription at the bottom of the account/subscription page. This won't affect your account in any way until your paid subscription time runs out (you then will be a preferred player with some limitations ingame, and read-only access to the forums) After cancelling the recurring subscription, you can buy the 60days non-recurring subscription or gametime-card codes to continue being a subscriber without auto-billing.

If you just book back the subscription fee, tell your bank not to pay the bill, let your credit card expire, etc. your account will be locked, and you need to contact CS to sort things out.

^^This.^^

Cancelling your recurring subscription does not immediately make you a preferred player. It just keeps your subscription from renewing. You will still be a subscriber until your paid time runs out.