Upgrade Prorata Fee Payments Not Fair

I have just requested an upgrade from Compact to Premium and the agent confirmed my prorata amount which I didn't have a probelm with. My problem is that I have to pay this prorata amount within 48 hours, for WHAT? I get billed every month and I thought it made sense for the prorata amount to be included in my next monthly billing. The idea of having to pay this amount outside of my normal billing really anoys me because now I have to cough up money way before my paydate to avoid disconnection. I am really upset and this is just plain unfair and I feel they bullying us into making these types of payments. Well in my veiw this type of practice is influenced by the rugby world cup and I cry foul on this one. I know that I wont get joy in all my attempts to reverse this but it doesnt make me happy at all.