ALOT of my frens faced this problem. Just sign up for Digi plan and you will not have problems being charged with excessive bandwidth usage as it is free usage on DiGi. Also, Digi is much faster compared to Maxis, I have compared with Maxis 3G loading the same site, youtube, etc. And it has still proven that Digi is twice or more faster than Maxis.

One thing I like to share with you guys also about Maxis service. I used Maxis fixed line back like 4 years ago. But as I have changed houses, I have terminated the fixed line. I am sure you guys know that we have to settle the bill before the line is being terminated right? So, yes I have settled the bill and had it cancelled off. So recently, when I wanted to sign up for iPhone 4, they said Maxis blacklisted me! I went to check with Maxis and they say I have an outstanding amount of RM111.52. Hey WTF is this? I cancelled it off and I still have outstanding amount with them? Ok I screw them up and down, the manager came over instead. After all those bullshit, he told me there's nothing we can do sir, just pay up. WTF?

I have a conclusion here, Maxis is a robber nowadays. They charge you for their mistakes!

I don't think they will entertain your appeal letter. They'll be busy thinking how to charge extra on their customer's bill instead.

Hmm, just wondering did Maxis provide a 50Mb limit (Megabit) whereas your watchdog captured 5MB (you hit your limit the first day), second day 20MB (roughly 200+Megabit). Could be the reason why you are being charged so much :/