Paying for 14 months but fresh installation needed because cables into the property were bad.

I have always been with virgin media. I moved to this property 30 months ago and have been on Virgin since then. I told them my Virgin had not been working, but no one listened. The engineer came today and told me that the Virgin cables hadn't been run properly, and he started a fresh installation from outside the building that the cables were faulty.  I had told the virgin right from the first time, but no one listened. I have been paying for the past 14 months with the most rubbish internet ever. It can't even get past the first room. The engineer who came today said he was surprised that my internet was working in the first place. Now, I want my money back. I have called the guys at Virgin, but the CS tells me I should have reported the issue when it wasn't working 14 months ago. Of course, I did, but someone hasn't logged it in. I feel robbed, and I am fuming right now. It doesn't help that the guys I am speaking to are from India, and one of them actually shouted at me and put the phone down. I can't wait for my internet to end in 60 days and go somewhere else. I need my money back.