snorkel mich is right..you'll need to call mbna to redeem points. it usually takes them 2-3 weeks for you to received(although they reserve the right to get them there to you in 6 weeks, but has never been the case), then you must complete the voucher and then mail to rccl directly.
when talking with rccl about when to mail by..they said you could keep mailing in vouchers up to approx. 2 weeks before your cruise just to ensure they get the voucher in time and can apply to your upcoming trip. I did the same thing as you, since the points are only good for 5 years from date of earning, I redeemed several different times at the $5,000 knowing that I'd probably not get to the free cruise in 5 years.