offered a deal via email and accepted and now the agent saying it doesn't exist

hey guys I gave my 30 days notice on Nov 1st and wasn't offered any really good deals until last 2 weeks where I was offered 20 percent off my original price which came in at 17.70 which I was very happy with accepted and had all the contract sent to me via email, then once the 30th came My services have all been disconnected so i called virgin to be put through to sales and they said the deal I've made doesn't exist, it has order number and full contract breakdown sent to me can anyone offer help? if needed I can attach photos of the contract sent, it also states the service will be active tue 3rd decemebr but the sales lady was adamant that it won't activate as nothing is there.