PvZ GW2 Currency Not Saving

I have attempted several times to purchase the in-game currency in Plants vs Zombies Garden Warfare 2, with the intent to open card packs. Each time I run into the same issue. I purchase the coins, they appear in game, I open a pack, and they are reduced to the pre-purchase amount. For example, I currently have about 10,500 coins. If I buy 120,000 more, I see my in-game currency appropriately increase to 130,500. If I then purchase a card pack for 75,000, it is reduced to 10,500 again. That math doesn't check out, and no matter what I do the currency doesn't seem to want to save correctly. I tried purchasing the currency through both Steam and the EA store numerous times. I have had tickets opened with both Steam's support and EA, and while I've been able to get refunds, I still can't buy the currency. Has anyone else run into this? What should I do? I just want to open card packs.