Vodafone is a Scam! How can I sue them?

I've been using Vodafone for the past 5-6 years. Recently, I moved to a postpaid plan and damn, I've been getting ripped off with inflated bills month on month. The response they've been giving me when I try to sort things out is outrageous, humiliating and absolutely out of logic. Though I've been having problems on the bill for many months, I kept walking up to their store, resolving them, month after month and paying what I have to pay. But there seemed no end to all this as they continued with their utmost poor service - they barred me again, without any prior notice, well before the due date arrived and I have no clue why! I'm fed up. I'm done. I want that company out of my country. I'm not pissed because their 4G is still acting like 3G, I'm not pissed because they provide very minimum to absolutely zero customer support. I'm not pissed because their signals are poor. I'm only asking them, why should I pay for whats not on the plan? I didn't ask for the "extra charges" and neither did I use them. What I've understood is that they've got a corrupted system under their skin. All the fancy advertisements are good for nothing. I've asked around, made my research on what the quality of their service has been in my 1st and 2nd circle of people and I'm sure this is a scam. To top this, they've sent me a legal notice! I spoke to a couple of lawyers who managed to reach out to me on behalf of Vodafone and they understood my plight. I didn't hear back from them. But today, a new advocate firm called up and spoke nonsense. I'm not even sure if they are advocates as all their information and charges against me are false. For example, "the telecom operator has been trying to reach you for 400days!" I stopped paying and using Vodafone since July only. I want to seriously take this up against Vodafone. I plead for advice to reputed lawyers on this forum on this because taking up against a company so big, is frightening. Will it be worth my time? (For your kind notice, if 10 people benefit out of what I do, I consider that worthy of my time)