The mount is not account wide, no. If you contact square enix support, there is a small chance they might be able to cancel the request, but I wouldn't hold my breath on that. Not much you could lose by trying though, besides however much time you have to waste talking with a representative.

While it's unfortunate you got phished, make sure to learn from it as a lesson to always scrutinize links anyone sends you, no matter what. Especially in these days when friends falling for a phishing scam can easily send you links with their hijacked accounts so you'd lower your guard.