I am experiencing the same issue.  I have tried to process payments for 3 separate clients.  I am getting the following error:

transaction was declined because the bank account is incorrect, or there is a security concern.

Strange enough, I have 2 separate QBs accounts (in the process of dissolving my other entity).  I have these same clients on my other QB account.  Because of the nature of one of their services (Tax Returns) I was able to process payments on these same clients.  Been trying to process their payments for their monthly accounting but QB has declined payment for all  3 clients.  

I have been waiting on the chat for an hour and half.  No response.  I can't get anyone on the phone.  I am very disappointed in the service.