Amazon Refund Request And Stop Charging My Acct

I am writing regarding unauthorized Amazon Prime membership charges that have continued even though my Prime account was cancelled at the beginning of April. My Amazon Prime membership in the name of Jane Haggerty was cancelled around the beginning of April, yet I was charged $14.99 on April 5 and again $14.99 on May 4 on my debit card. These charges are appearing on my debit card even though I no longer have an active Prime membership. I have tried to contact Amazon customer service about this issue but have not been able to get through and therefore have not received any explanation or support. I request a full refund of the unauthorized charges for April 5 and May 4, and confirmation that my Amazon Prime membership is fully cancelled and that no further charges will be made to my debit card.