I've contacted Three on their online chat service. I wanted to change the date of my direct debit from 12th of every month to 15th of every month. It was a right palaver and the adviser didn't answer many of my questions and really confused me. He did say there would be a charge which would be the days in-between my current billing date and my new billing date. I never go over my allowance of data, texts and phone calls and pay £43.40 per month. Please can anyone tell me what the difference in my bill will be in next month's bill? Thanks.