Aircel — using 99 rupees plan for GPRS unlimited download but they charged me 7000 rupees

Dear Sir/Madam,
I am using aircel postpaid connection (Mobile NO--[protected]) using tariff plan-50 having 98 rental per month for unlimited GRPS use.
I paid my previous bill of 105.00 on 15-june-2009 (due date was 17-june-2009)
I received a message from aircel that my credit limit has been exceeded for the current billing cycle.
As per plan my credit limit in 750 rupees
but when i checked my unbilled amount from 1212 (toll free service), i came to know that my unbilled amount is 6416.80 rupees
When i enquired about this on 121(toll free service), one of the executive told me that my bill is 199 rupees
But just after 15 minutes i got a call form your another executive that today is last day to pay my outstanding amount of
6416.80 rupees.
Now my major issue is if my credit limit is 750 rupees then why didn't aircel informed me that my limit has exceeded
Moreover i didn’t use the same number that much.
Aircel Executive told me that i used the same in roaming or through wrong URL,
If the matter is related to wrong URL, , then they should send the detailed bill with my internet usage details
and If the matter is related to roaming then i was never informed before that i will be get charged for GPRS usage during roaming.
Even till now i didn’t received any detailed bill, stating my usage in roamimg.
Do some needful





Ruchi Tyagi
Tariff Plan-- Plan 50
Account Id[protected]