You could make a complaint about being given wrong info in the phone call but I don't think you have a leg to stand on looking for a reduction in rate if you willingly signed up for a fixed rate in November, fixed rates are not reduced during term, they are exactly what they say - fixed.
If the variable had gone up would you have been ringing saying sure increase my old fixed rate there to match it's only fair, the whole point of fixed rates is you know what you are paying for a fixed term, after that it's swings and roundabouts, rate rises you win, rate drops you lose.