I've shot you a message eminem121416 and refunded the payment.
Unfortunately I have never found an easy way not allow double recurring subscriptions to be active. The vBulletin paid subscription system is pretty archaic. The system will credit you the time (If your subscription expired May 15th, and you purchased a month, it would change it to June 15th and then if your billed again it will change it to July 15th).
Let me know if your still having troubles.
Sorry about the problem.
Fry.