Cancellation requested in Aug 2017

I have several times send through by email a request to cancel a ADSL line. This request was done 14/08/2017. Now they have eventually cancelled it after several enquiries. BUT now they charges us for September as they have only cancelled it on the 14 September 2017. Yes one months notice was given and we paid for August, but now we must pay for September as well. THIS IS NOT ACCEPTABLE. Please refund both land lines. ********** and **********