the way xxx company's broadband calculate the BILLing~~

Finally!
I understood what the broadband staff told me!
Ok! Now, allow me to explain it to you all!
First of all, I sign the contract to get xxx broadband on 9 September 2009 and the first bill was came on 16 September 2009, so the first rebate of RM30.00 is counted in! (when I was sign up the broadband, it is during promotion. So the original price of that package was RM108 per month and rebate RM30 per month until 1 year)
Means that, 16 Sept 2009 to 16 August 2010 it was already 1 years (12 times rebate of RM30). So, I had been charged of RM 108 (original price) on the bill of 16 Sept 2010! And because of I terminated the broadband on 22 September 2010, the company charged me another 6 days (16 Sept to 22 Sept) of it original price!
(22-16)days/(30 days)×RM108=RM21.60
It charged me another RM21.60!
It means, if I want to terminate the broadband on 22 Sept 2010, I have to pay a total amount of RM 108 (so-called 13rd bill) + RM21.60 (6 days extra usage) = RM 129.60
OK! That’s all about the bill and amounts have to pay!
Now, I would like to ask some question. Really doubt on that!
1st: When I sign up the broadband, the person (maybe can call him as agent) didn’t explain how the company will count for the bill to me! To have a legal contract, doesn’t it means we need to exposure MATERIAL FACTS? I still remember that, EXPOSURE MATERIAL FACTS is 1 of 6 components need to enter a legal contract or else, the contract is VOID! It means that, there is no contract since the beginning! Am I correct?
2nd: I doubt that, if I go and terminate it at 17 August 2010, would it charge me the RM15 of the rental of modem because of terminate before 1 year full? I really hope that anyone can go and try it and then reply me here! I really wonder…!

Ps. I am not offence, I just want to let everyone know how is the way they calculate for the BILL. And I am really doubt and confused with the question above.