What does effectively mean on a contract?

I'm off on contract but it says effectively £24 a month but above it says Voda Band 1 iPhone £33 24m (24 months) :L what does that mean? How much would i be paying a month?

YOU HAVE TO PAY £33.00 PM, THE D/D WILL BE FOR £33.00

After you claim your cash back (the rebates) it means that you end up paying £24.00 PM

You pay £792.00 you get back £216.00 rebate. You have paid £576.00 effectively £24 a month

Please BE AWARE IF YOU DO NOT FOLLOW EXACTLY THE Way TO CLAIM THE CASH BACK YOU MAY LOSE SOME OR All OF IT
So you need to be sure you know beforehand what you have to do as late claims will not be honoured