How long is refund? I’ve never received it..?

So I got a refund on an app that purchase a subscription I’ve never attended to have and received a refund but never got it? It purchased through my debit card. But I’ve never got a refund on that following day... If its purchased through my debit card? Does it mean, it’ll go back to my bank? If so I’ve never received it. I am not sure if it take days or so to return back. Please help.