Late payment charges on bills

Gettingtherequickly

Hi

An odd one here.  We own 4 business units which were tenanted until 2 years ago, we are currently converting them, so clearly liable for any charges.  However, for one of the units we never received a bill until we received a debt collector letter last week.  At this point, we discovered that although the other units incur costs from one water company, this unit is billed by another, who had been sending the bills to an empty unit.  They then sent a bill to the office address in January that arrived the same day as the debt collector letter.

I tried to speak to someone, on hold for 30 minutes each time and then the line was completely  inaudible, so they hung up.  I tried to use the online chat option, who told me it was our responsibility to establish the supplier and then cut me off.  However, as 3 units are supplied by one company, and indeed is the only company that we can deal with regard to the water supply to the units when they are residential, it is somewhat unfair that we are expected to guess that there is a separate supplier to 1 unit.

We have no issue in paying the water charges, however it is unfair that 2/3 of the bill is actually the late payment charges & interest. Any suggestion on how to get these charges reversed?