cancelled - but still paying

Cancelled both contracts via email at the beginning of April 2018, Nothing has been done and I still had to pay for May 2018. (automatic debit order I cannot stop) The system is not working. When the alarm goes off - no response. The other system has been not been working for the past 18 months to 2 years. They promised to phone me yesterday. Waiting in vain ofcourse as happened before. I have requested a refund.