Trying to redeem gift card

I got a gift card for christmas and it has a remaining balance of $20.03, I I have been trying to use it to purchase a sims 4 expansion pack thats $37,  I have tried selecting both paypal and 2 credit cards to pay the remaining $17 but the ea app and website will not let me. Support told me I could add the remaining amount to the gift card but the only options are to add $15 (not enough) or $25 (leaves me with a balance leftover again which leaves me right back where I started. Is there no way to use the giftcard and paypal or credit card? I dont want to just fork over my money that ill never get back and get stuck in an endless loop. I looked at cheaper options but everything close to the amount is conveniently $20.85. 

Does anyone know how to add a custom amount or how to use two payment methods. This whole experience makes me never want to purchase EA gift cards or ask for them again since I cant actually use them. I am thinking this can't be my only option. I am hoping it's not.