Please cancel my membership

My contract came to an end on the 31 January 2016. On the 3rd of January 2016 i wrote to virgin active notifying them that i wont be continueing with my membership when my contract came to an end. They increase my membership amount, and billed me for February which i reversed the order. Now im being harassed by emails saying my account is in arrears. I plan on going back to them later next year, but dont wanna go back and find that i owe them. Can you please stop with this haras*****t and cancel my membership.