Yes, they have to return your debit card (and anything else you left behind) when they remove you. There is a word for deliberately holding onto *any* of your property and not returning it to you: theft. If they did this deliberately, you could look to file charges against them (e.g. vs. the bartender; possibly vs. the bar, too) and to also sue them for any costs, losses, etc. you thereby suffered (for example, if they then used your card and took any money out without your authorization). If it  was not deliberate, you could only sue for any losses, not press charges, since if it was not deliberate, they would not have had the right criminal "intent" ("mens rea") for criminal liability.