Due to the problem of the “unsubscribe” button not working, 
I have tried several times to cancel my subscription and all I get on the screen (Subscription failed to cancel).
there were not any options to contact support.

Then I even I deleted my team. and when I create new there was only free miro.

And Miro still keeping me mail that my payment decline.
But I have no idea how to cancel subscription.

To delete account - does it help? Because I have other chance to contact with Miro that they to stop request money. it is seems they just only want my money :(

Zena