CIT Technology Fin Serv, Inc CIT Financial Billed us incorrectly, applied payments incorrectly, then sicked the collectors on us. Internet

CIT bought our office equipment lease from CITI financing.  They began invoicing us, but their invoices did not break out the lease and taxes, and they only showed a balance due - nothing specific at all. 

We continued to make our payments (they don't really change from month to month), but they applied our payments to another customer's account.  Then they started charging us late fees and interest when we told them they were applying our payments incorrectly. 

They were unable to reconcile our account, but continued to insist that we owed them money. 

At the end of the lease, they realized that they had screwed up, but insisted that we owed them for property taxes, and would not allow us to return the equipment until we paid them, even though they could not provide us with a listing of unpaid invoices. 

Finally, they sicked an aggressive collector on us, who called everyone and everyone's secretary, pulling people out of meetings with his urgent requests for payment, and threatening lawsuits.  Too tired to work with them, we offered to pay a sum that was about 1/5 of what they said we owed.  They immediately accepted, as long as they could have the payment posted to their account the very next day.  We still don't have a return address for the equipment.  I guess they don't really want it!  Clearly they were just fishing for more cash.

Very unprofessional and incapable, from start to finish.