This just happened to me as well.  2:39am I received 3 emails that they were closing my account and a transfer of funds had been initiated with no calls, heads-up on anything prior to that.  Had the account open for 4 years with no issues.  Where are the funds being transferred to?  No idea, and it's a lot of money.  

No customer service agent has a clue why and just kept saying "our operations team needs to review this and will get back to you in 1-3 days".  That doesn't help when you need to pay bills from your checking account.  It's been 2 days and still nothing from them. 

I will be closing down my Quickbooks accounts for all of my business due to this.  It's absolutely insane.