I have a prepaid number in my N9. So whenever i make a call, sms etc. I get a dialog box with usage details and charges.
The signal strength where I live is poor. So mobile data disconnects often and again connection is established and every time I get that dialog.
Now the problem is that if I leave the N9 with mobile data ON for a while then it does the above, and many such dialogs are stacked. And next time I unlock the phone, I have to sit through and dismiss each one individually. This is very frustrating as once I sat for 10 mins doing the same. The phone is virtually useless in that time.
I used a Symbian device before, where there is an option to dismiss all, so never experienced this before. It is very very annoying.

Is there a solution to this, like dismissing all? I don't want to disable that dialog completely as it is useful (anyways how can that be done?).

I guess that is a 'convenience' feature of you provider.
It may be useful, yes. But I have no idea how to disable on N9.
So I would ask the operator to stop that.

Dpending on your provider. It might work to dial

*121*57#

Otherwise. You will need to call the provider.