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Please see below for my story. This happened two years ago and I immediately switched providers as a result of this. I also now have a "default" on my credit history so am taking action to have this removed and rectified. I am more than happy to pay this bill once it has been correctly calculated and I have been provided with a breakdown of this.
If anyone has been in a similar situation, please advise how you solved it. Vodafone have been absolutely useless (as you will see below) and not being a customer anymore has made solving this even trickier. I have just submitted another complain to Vodafone regarding this, though in the past this has not got me anywhere.