Billing increase, without notice

[#1]

So, I was a Plusnet broadband customer and the speeds were unbearable. My area finally got with the times and we can now get fibre broadband. I have an email stating that the Monthly payment would be £15.50 and that I am on a fixed price contract, which means that the broadband will not rise. This also then states that they will email me with any price increases on my contract. 

My last payment that wen't out was for £23.50, which is not the price stated when I took out the Fibre Broadband. Nor is this the price stated in my billing email from Plusnet. I know it's only £8 a month extra, but it's the fact that the offer was there for £15.50 a month, yet I sign up and they charge me more? I've tried to call plus net and the 'billing system is down'... call back. I've tried online chatting twice on separate days, and low and behold.. the 'billing system is down'. So I've resorted to this forum. If anyone could give me a heads up, that would be great. I just feel like, I was duped into an 18 month contract. 

Many thanks in advance for advice. 

[#2]

Hello @Dirtylibrary,

I am deeply sorry for the experience you have had and for the errors that have occurred with your billing. I have looked into the issue for you and responded here via your account explaining the corrective actions I have taken.

I am unable to detail it via the forum due to your account containing account sensitive information.

Should you have any concerns, please get back to me via the ticket directly and I would be happy to address them.