If you cancel a subscription do you get a refund

When you cancel a subscription it continues until the end of the current subscription period. Apple seem not on the whole to be prepared to refund a subscription, though they may be sympathetic in cases where one was started accidentally (by failing to cancel in time during a free trial, for example). You've nothing to lose by asking, tbough they are under no obligation to refund you. https://reportaproblem.apple.com/?s=6

Note that just deleting an app doesn't cancel the subscription. (To cancel a subscription please see How to cancel a subscription from Apple - Apple Support).

No.

You can request a refund using this procedure:

Request a refund for apps or content that you bought from Apple - Apple Support