I know I bought something on iTunes and I got charged but my credit cards doesn't work anymore. It won't let me update or download any apps. Could I just go buy a 20$ iTunes card and will it charge that for the past failed purchase? Help please

could I use a 20$ giftcards from iTunes for a failed purchase Instead of a new credit card? I'm not going to add a new credit card to my account. When I try to update or download a new app it tells me I have to update my billing. So I can't do anything about it because I don't have a new credit card and I will not be getting one. I just want to use a 20$ gift card so that past purchase could just take it off of my giftcards I will add. Will this work?