I had an identical situation happen with Nova Scotia Power Corp... coincidentally, also for $1,000 (but in 1978 dollars), and with one more wrinkle. I was living in one of the three units in the building. (There must be something magical about $1,000 receivables that makes a utility decide to get nasty.
)
I could not get NSPC to back off, and ended up paying the bill. They were threatening to cut off my power for non-payment, so discretion was the better part of valour.
If I had had a choice, NSPC would have permanently lost a client that day.
In another issue with Maritime Tel & Tel, I wrote the president of the company directly, to register my complaint about the service. It worked. My issue was resolved satisfactorily. I received a credit for future service. The best part was that MT&T was a monopoly at that time.
The moral is that is, if you find the right person to talk to, and put your position forward in a non-whining, but forceful manner, you may get satisfaction... even with a monopoly.