Tata Indicom Broadband — Broadband usage

Dear Sir,

Tata indicom broadband records indicate that we have done 3.5 GB o[censored]pload during a single day, which is impossible. We have licensed antivirus and all our PCs are virus free.
The usage limit for our account is 20GB, due to mistake in records indicating 3.5GB upload the usage limit exceeds and we have to pay huge amount for additional usage...
This is being repeated for 2nd months. Even after registering complaint nothing happens, we have been sending emails to Nodal office for pune and appilite authority but no solutioin given.
Username: [protected]@vsnl.net

Thanks
Amit