BSNL — excess billing as well as poor response from BSNL

Sir, i have been using BSNL post paid mobilse corporate CUG plan-299 with gprs plan-199 unlimited internet connection
they have sent me a bill of 5000 above in which roaming charges counts to 3000+ showing that my roaming outgoing call time is aroung134 hours which looks rubbish as i was in roaming for 7 days.
when i have contacted the bsnl office on 03.03.2008 for the first time, i was advised to request for an itemised bill and received it 0n 28.03.2008 after a series of phone calls to bsnl authorities and i was asked to send this bill to the concerned A.O. to settle the matter again. he asked me to fax the bill and i did so.

If they have billed me wrongly, i could not understand why i should again spend money and do all these to prove them and moreover they have barred my outgoing even before reaching the credit limit of 10000 thay provide me

i could find asingle person to whom i can contact and have my grievance solved in bsnl
also the same is the response from the bsnl customer care i.e., 24365