If a cancel a subscription minutes after can I get my refund back?

Usually you can get a refund, unless you make a habit of doing it. Here is a one-stop link for billing questions→Subscriptions and Billing - Official Apple Support. You can review your purchase history, cancel a subscription and request refunds. First cancel the subscription, then request the refund. If the automated system rejects the request use the Get Support link at the top of this page and ask an actual human being.