It's normal - the way VM apply their price rises they are amplified by any discount a customer gets. On the most heavily discounted deals (eg the Big Bundle for new customers) the discount can be around 50%, and a skilled retentions game player can get those prices. However, those customers see an increase of roughly double VM's claimed 13.8%. The logic for VM is that they sell (as often as possible) fixed discount deals not fixed price, and that allows them to put up the underlying standard tariff. The maths here is that is that the customer's new price will be the result of their current discounted price multiplied by 1 + ((RPI+3.9%) divided by (100-XX)), where XX is the percentage discount of the customer's package to original full price. If working through those calculations, make sure that you get your brackets and decimals in the right place!
And next year, due to a change in the T&Cs you will get the same stonking price rise but won't be able to cancel or renegotiate as VM are changing their terms to stop you.
But none of this affects me. I've already left and I'm with a smaller ISP on a twelve month fixed price deal. When that ends it will undoubtedly go up, but as this smaller ISP don't do the massive discounts + userous price rises that all the larger ISPs have adopted, I don't anticipate anything much beyond a CPI increase. But if I'm wrong, and they wheel out a 50% increase, I'll be a free agent, with no tie in, unlike VM's customers who'll be staring out between the bars, wondering why they agreed to be locked in. As an alternative to the smallest ISPs, consider Zen Internet who'll do you a fixed price for 18 months.
