Wish Net — provider takes more money and unauthorized charges on top of gst

Address:

Kolkata, West Bengal, 700032

I have been a long time customer of wishnet broadband. My provider has always been very shady about the internet fees not allowing me to pay online and also not letting me know about the taxes involved. Recently i found out that wishnet charges 18% extra service charge on their tariff plans. So by that calculation the prices of the present packages are:
Bronze 25 base price: 499 after tax: 588.82
Bronze 30 base price: 549 after tax: 647.82
Now, for over the past few months i've paid rs. 650 for the base plan of bronze 25, when i should be getting bronze 30 instead. I initially brought the matter to their attention since i thought rs. 150 was too much for tax since i didn't know the exact rate, but they said that this was the price for the base pack.
Also i would like to mention that this service provider has been cheating me ever since i've taken their connection. I have always payed above 600 and always received their base plans. I believe wishnet should make the payment of their bills a more transparent process. As of now it is too shady and i want to make a complaint of that.