Gift card wont redeem

I am trying to redeem the remainder of a gift card in my EA wallet but the amount isn't enough to cover the full amount. The EA store both in the app and on the website won't allow me to pay the remainder with credit card or paypal. I asked support for help and they told me to add additional balance to the gift card to make it enough to cover the purchase but I cannot find a custom amount option and if I add one of the preset amounts I am either still under the needed amount or over and back where I started with left over gift card. I just want to use up my gift card and pay the rest on credit card or paypal so I don't have any balance left over. Ideally I dont just fork over more money I cant spend to spend what money I have already paid.