Let's say I want to buy Redmi Note 4G and I pick the 108 plan.

1) What does it means when it says Upfront Payment - Rebated throughout your contract? Does it means like, after the first month of rebate from Plan Advance Payment, I get some / all rebates from it for my monthly 108?
2) When the contract says it's 24 months, does it mean that I have to be a Digi user for 24 months, or I have to use 108 plan for 24 months?

Thanks.

2) Do I have to stick with 108 plan for 24 months if I picked it when I purchase it? If not when and how can I switch to other plan, like 50 per month? Also, is it possible to change the postpaid number to prepaid, and when and how can I do that if it is allowed?

Thanks