I have been trying to cancel my subscription a day after I subscribed for the trial period but manage subscriptions option is not working at all. It's ridiculous...
I hope you're doing great and, sorry for the issue you're experiencing.
For cancellation and refund, you need to connect with the particular store you purchased the application from; as Adobe does not issue refunds for purchases made directly through app stores or the play store.
For cancellation and refund, please refer to these articles:-
I hope it helps.