One star, but only for spelling their name right. ...

One star, but only for spelling their name right. Incompetent and unpleasant managers of our Manhattan coop.
DE sent me an erroneous invoice for January, 2017. I told DE that I would pay upon receiving a corrected invoice. February invoice compounded their error. DE failed to send correct invoice in spite of many requests. Same for March, April, May, June, July. Property manager was insulting instead of helpful.
With erroneous August invoice, I decided to pay correct sum due for January, in spite of DE's failure to send me a correct invoice.
Spoke to DE office about erroneous September invoice, and was told that the overcharges were due, not to DE'serrors, but to an Assessment to all tenants. Three fellow tenants confirmed that they were not charged any such assessment. I confronted DE with their misleading falsehood, and they told me that the charge will continue on my future invoices.
Avoid hiring DE like the plague.