Three Still Takes Payment For Cancelled Contract

Three Still Takes Payment For Cancelled Contract
Up until October 2017 I used a Huawei dongle (black with green '3') to acce ss the Internet. This was on a monthly billing plan of £16 for 5GB. I
was never charged more than that.
Then in October I cancelled that plan with the agreed one month notice. And I replaced the dongle for a Huawei mobile / wifi device (white). This was at the rate of £17 for 20GB a month for one year.
However since then I have always been charged well over £17.
And checking my bank account I see that I am also STILL paying the £16 a month for using the old dongle despite cancelling that contract.
Three remain unresponsive as to what is going on.
Update Feb 2018
And despite attempts to get the dd cancelled I am STILL paying the direct d ebit for the previous cancelled contract, PLUS the direct debit for the new one.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a site by and for consumers of financial services and advice. We are not affiliated with any of the banks, financial services or software manufacturers discussed here. All logos and trade names are the property of their respective owners.

Tax and financial advice you come across on this site is freely given by your peers and professionals on their own time and out of the kindness of their hearts. We can guarantee neither accuracy of such advice nor its applicability for your situation. Simply put, you are fully responsible for the results of using information from this site in real life situations.