Account deleted but annual fees charged

Dears,

Last month, I tried Prezi with the free month of Prezi Pro version. But it finally didn't have the utility expected, so I decided to cancel my subscription. At this moment, i had difficulties to find where to unsubscribe in account / settings and i ended up deleting my account thinking that it will also prevent to be charged.

I have recently be charged for the full annual fees.
Is there something to be done to be refund please ?
The Pro account is deleted and it is a recurrying paiement. So will i end up in the same situation in one year also ? I can no longer unsubcribe.

Thank you for your help,
Best regards,
Romain