A few things:
1. You can't "work harder with Apple". Apple is a black box. They have no department waiting eagerly to help out developers. EA themselves cannot get Apple to up their gift code limit. As much as I like iOS as a platform, they are basically like Youtube in this regard: "either get with our rules or get out".
The most obvious example of Apple's fair, but stiff approach is their bug database. You can submit bugs to Apple regarding iOS, OSX, etc. They will tell you the resolution (i.e.: solved, duplicate, as designed) but developers have no access to the list so they can't tell if a bug was already filed, what the actual fix was, or if that fix is ever coming.
2. In theory, IAP (such as the season pass) is a lot easier to fix because it's just about setting a permissions flag. But not explaining that up front was such an obvious mistake.
3. As explained, it's absolutely possible to have multiple account regions on your device. As someone who has lived in multiple countries I have done this for years. A bit of a pain at times for updates, but it does work. The only problem is - just like with PSN/XBL - you need a regional gift card or credit card to put money on it.
4. Yeah, you would think Apple would solve the whole thing, particularly given the power of Kickstarter these days. But if there's anything we've learned about them over the years, it's that games are just another genre of app. :/
Though I'm not an iOS backer, if I were, I'd actually be paying 13% tax on the $5 price of the game, which makes it kind of a bummer to receive a $5 refund.
And this is why you need to email their support. I'm pretty sure Camouflaj would refund you the exact amount. They have been nothing but helpful in that regard.