Just after people opinions (or fact if they know the specifics of the laws involved)

Got cold called by Power Company to switch to them, we were thinking of changing so let them do the spiel and comparison. We liked the idea of a fixed price for Gas as we use a LOT during winter (central heating) and was advised price was $129 per month for suitable plan. I was checking online on their site whilst on call and noticed online that deal was $149, so I asked for confirmation of the price, which was again given as $129.

Get confirmation letter other day, the fixed price is shown as $149 p/m.  /sigh. Ring company, they investigate, and they confirm I was offered the deal at $129 p/m, but they were going to conduct a review of the case and may not honor it.

SO I am asking - is this legitimate? This is not a mis-labelled price tag this is a verbal offer over the phone that I made them confirm at the time. If they decide to not honor the offer do I have a leg to stand on or can they just claim it was a mistake - bad luck?