MBD and Virgin Active

I had cancelled my membership with virgin active last year June, and i had paid all my membership dues to them during this period. I then receive a message from MBD telling me that I had a balance outstanding which i knew was incorrect. I then contacted MBD and they had ask me to provide proof that i had cancelled my membership and have no outstanding balance yet they still expect me to pay the fee? I had contacted a member from the virgin active team and they supp**** me with a letter confirming that I have no outstanding balance and they date of which my membership was cancelled. I am very unhappy and will not be returning to virgin active if this how I am being treated after being a diligent customer and paying all my membership. Please remove me from the MBD system because i have paid everything.