Netshort Subscription Cancellation and Refund

I am writing regarding my Netshort weekly subscription, which I attempted to cancel but continues to be charged to my credit card. I originally subscribed directly with my credit card because there was an offer for 6.92, but afterwards the system did not allow me to cancel my membership. Around 20 March, I contacted Netshort customer service to cancel the membership specifically to avoid any further charges. Despite this, my account has been debited 19.99 twice, on 25 March and 31 March, for the weekly subscription. I have spoken with customer service a total of five times about this issue, and my customer ID is 1973543761536606***, but the problem has still not been resolved and the charges continue. I request the immediate cancellation of my Netshorts account and a full refund of the two weekly charges of 19.99 each taken on 25 March and 31 March. I also expect written confirmation that my membership has been cancelled and that no further payments will be taken from my credit card.