False expectations and sales

In November 2017; when my LTE contract was at its end, Jason from telesales department called twice daily. I was going to terminate but he advised I could get double the data at the same premium or the same data at apt reduced amount. I was on a 20+20 do understood it would now be at 40+40 as per their current offer. I advised I did want or need a router . I renewed telephonically against good judgement and have exactly the same data af the same premium . Despite monthly complaints, there's been no resolution or adjustment . There customer department advised me take the issue up with sales. All I want now is a termination of their contract and they can keep their unused router which I didn't want . I'm tired of losing time and energy telephonically over misrepresented sales.