Did they inform the customers in advance? Which accounts and why?

为什么关帐户呢？

虾米？啥破事儿啊？为什么啊？

what kinds of account? cc/checking/saving/mortgage

Citibank 有这个传统，关闭inactive超过两年的credit card account without advanced notice. 节省银行的开支，很正常，不会伤害account holder 的credit history。