Struggle to cancel

I attempted to cancel my openweb account since September 2017 via e-mail as well as on the website. After not receiving a response I disputed the payments from November 2017 and recieved an e-mail for non-payment on my account...this matter was eventually resolved in February 2018. I recently recieved an e-mail from a debt collector saying that I owe openweb money for the months before cancellation.