Quickbooks online account hacked

Our company uses Quickbooks online for sending customer quotes and invoices. In the case of quotes, we normally ask for a deposit from the customer before work commences. About 10 days ago we sent a customer a quote and he paid the deposit but it didn't end up in our bank. Upon enquiry, the customer showed us the PDF quote he received where our bank details were changed so this money ended up in a ********** account. We contacted Quickbooks and our audit trail was checked and no fault found. It seems that somehow Quickbooks had been hacked and our data compromised. We raised a ticket qith Quickbooks (Case nr :***) on the 20th June. Despite several follow ups and advising of the urgency of the matter, they are still investigating. We have lost the deposit money and propbably a customer as a result. How can it take Quickbooks more than a week to investigate an urgent matter after the issue was escalated to their higher team. The support from Quickbooks has been appalling. Next question is, how secure is our company data? What if this was not a one time occurence? Quickbooks is quick to disable your account in the event of non payment but what if we are the actual losers? Is Quickbooks going to refund the ********** amount? There have been other users which have had their Quickbooks account - just Google the issue. We need answers now!