Usage Notifications - Some way to avoid overage charges?

[hiyuu3]

I was just charged for overage usages but I want to avoid this for future cycles. Is there a way to just disable my data when I reach my limit instead of it just using data I didn’t pay for and being overcharged for extra? When I reach my data limit I would like for it to just end there and not access extra. Any way I can enable this? 

[P3t3y]

I overused my data for this billing period, so I bought the 2GB add-on. It says the add-on is active, but when I go back to the usage page it still says I have exceeded my data. Can I keep using data this month or will I continue to be charged overage fees? It also said if I added at least 400MB the overage fees would be waived, but I’m not seeing anywhere that the fees were waived since purchasing the add-on. Thanks

[AP12]

Well this is my first time when I used my whole data and I didn’t get and notifications so I keep using it. But then I checked I found that I only use 3Gb over use data and they put 60$ cost for extra 3 gb data. That really bad. After this I make my mind to change my sim.