Shopify auto deducts charges from my account without my consent

[Tajr]

I opened a trial store in Sipify and used it for about 15 days. Then I abandoned the store as there was no traffic to my store, assuming my store will be stopped if I did not pay bill for next billing cycle. Shopify auto deducted $25 from my account on 1st Nov without me having a consent. Now the question is how I close my store permanently so that no recurring charges are incurred? Is it possible to get my $25 back as I am not using their servies anymore?