False advertising on website-reneging on honoring advertised price

Saw a 50mb/s uncapped LTE package advertised on their website, which I attempted to subscribe to. After the consultant got back to me, and I sent them a screenshot from the website, they told me that no such package existed, and that they would query it with their manager. Two days later I contacted them again to follow up, and was told that when they queried it, they were told that it was a mistake, and the manager could not help them. I then checked the website again, and it had been changed to reflect as 20mb/s.

As mentioned above, I have a screenshot of the original adverti*****t. To my mind, this constitutes false advertising, and is in breach of the consumer protection act. I am willing to take it further if necessary.