Airtel — charged money over credit limit

I frequently travel abroad and in one of my travels to serbia for which i have international roaming pack, airtel said that my network was latched to the mobile network in macedonia which should not by my problem as i didn't travel to macedonia.
I was charged more that 290000 in bill.
1.) first of all this is an uethical bill which i won't pay.
2.) even in worst case if i consider that fact that i have to pay some money then i have been charged higher than my credit limit with airtel. My services should stop or i should get a notification at the point where the credit limit gets crossed.

I asked airtel for disconnection!

Mobile number: [protected]