Unreasonable billing on my postpaid number

I own mobile network i have opted for 199 i plan. which I modified in between month for which i have been charged 5430 on pro ration based. my credit limit was 1650 and company did not intimate me about credit limit and also according to guidelines of trai customer should be intimated about his credit limit and should be also intimated on reaching 80% of his credit limit. and also there is no where explained about pro ration CAF, Startup kit, ideacellular.com, myidea app. Just because the number is postpay comany can impose any amount over the customer and barr the number.