On the power pole pretty much next to the meter
Since you asked for a switch, you're going to want to contact the power company and request a copy of any service contracts relating to the property. You need to verify you didn't sign something agreeing to be responsible for the consumption of the light.
If there is something in there that in any way could be construed to read as you accepting responsibility for the light -- you'll likely lose any attempt to litigate it. If there is not -- you need to determine what the damages were. To get anywhere, in that regard, you're going to need to show what you paid for in services during the period in dispute. Ideally, that would be billing data. If that's not reasonable to obtain, you can check your own bank records. While it may not be possible to obtain a record for every month going all the way back a decade -- you need to be able to show you made an effort. Record everything you do in these efforts, record the time you spend on the phone, record the time you spend doing everything.
Any conversations you have with these companies should also either be recorded or transcribed, former being preferred -- be sure to know and abide by the law(s) of your state in this regard.
There are a number of ways you can approach this -- one of which is obviously to be pissed off and convey that when you talk to your power company -- of which I can assure you is the least productive options at your disposal.
-Try to work with the power company to come to a resolution
-Contact your state utility commission and see what, if any, process they have to handle something like this
-Hire a lawyer and sue them (Your contract may have an arbitration clause that would complicate this)
There may be other options you've got, those are the big 3 the come to mind. My personal feelings, were it me, I'd just want the utility to refund me a fair amount for the period in dispute. If litigation or arbitration can be avoided, I'd do my best to do that. If not, expect them to drag it out for years and make it as annoying as possible. They have staff lawyers, you don't.
So, three things:
1) Be able to show you didn't sign anything agreeing to be responsible for the consumption of the light
2) Be able to show what you paid during the period, or that you made an effort to gather than information
3) Have a number that you will accept
You want to have, at your fingertips, all of the pieces necessary for all parties involved to resolve it. Expect it to be a slow process, this is not likely something they deal with very often -- especially over such an extended period of time.
