Baycorp debt collection agency?

I received a shady-looking 'please call us now very urgent' text with an 0800 number written on it, called it, turns out to be Baycorp. They claim I have accrued a $190 debt with a power agency I have never even heard of LAST September (and I had received no bills for such!). I asked the lady on the phone what the address associated with the power bill was, she harrumphed and haaed for 5 minutes before finally listing my old address.

She promised to send me the invoice for the bill, so we'll see what becomes of that. But what do we do if I genuinely have never signed up with such a power company or it isn't our bill? It seems silly to pay for legal advice over $190 but this seems a lot like extortion. I googled Baycorp and read that they actually have the power to screw up my credit situation and there is no disputes process for this.

If I faced something like that, I would first settle the 'outstanding amount', prevent ruining credit history and then raise a dispute with concerned.

Is there a way I could raise a dispute without paying a lawyer?

Try the Citizen's Advice Bureau for help.

Baycorp receive proof of debt from the company that lodged the debt, so you could request a copy from them.
Whilst they may not have a separate disputes process, they do need to prove their claims otherwise they are effectively being fraudulent.

In addition to Citizens Advice, many areas also have a community law centre that can offer advice