Netshort App Store Subscription Charged $89.97 After Cancellation

I am writing regarding an issue with my Netshort app subscription through the US App Store. On 19 February, I attempted to cancel my subscription via the app and believed that the cancellation had been processed correctly. Despite this, I have continued to be charged for the subscription after that date, and the total amount that has been taken since 19 February is $89.97 USD. I have no customer number or subscription ID available other than the information linked to my Apple ID in the US App Store. I have not yet been able to contact Netshort customer support about this issue, but I would like this situation to be resolved as soon as possible. I kindly request a full refund of the $89.97 USD that has been charged after my cancellation attempt, and I also ask for written confirmation by email that my subscription has been fully cancelled so that no further charges will be made. I expect this matter to be reviewed and resolved promptly.