iTunes gift card

So I was gifted a 3 set of $10 ($30 total) of iTunes first cards. I had $8.55 then I added The first two, the money 2 went on smoothly making my balance $28.55 then I was in a bad WiFi area adding the 3rd and it scanned fine but then an error occurred and it wanted me to do it again. I waited til I was in a better WiFi area to try again, as I did so it says already redeemed however my balance still remained $28.55. So how do I redeem this money ?😭