Reliance Data Card — data card deactivated without a ground

I purchased a reliance data card no. [protected] two months back. They abruptly deactivated data card on 25.3.2008. On enquiry they explained that it was exceeding minimum limit of Rs. 1200/- and requested to deposit atleast Rs. 500/- to reactivate. When approached their Borivli centre on 28.3.2008 they said bill of 1074/- dt.22.3.2008 having due date of 10.4.2008 should be paid in full for reactivation.
The bill is not raised / couriered to us, and due date is also 10.4.2008. Then why they harrash the customers by deactivation. No person attends to complaint, stating deactivation is computerised.

We should have a forum to take them to consumer grievence cell, They misunderstand that it will not be feasible for a consumer to fight them for a small amount, and they will manipulate a huge amount from mass consumers.

Please advise a consumer forum for serious fight against their abrupt behaviour causing harassment.

s.k.gupta