Unexplained 10 GB Usage and High Cancellation Fees

For a long time I have been a Turkcell customer, but I constantly experience mobile internet connectivity problems despite paying ₺1,150 every month. I frequently cannot use my internet properly, yet I am still charged in full for a service that does not work as it should. Whenever I contact customer service, I receive the same standard response that there is maintenance work in my area, but the issue is never actually resolved. Most recently, two days ago, I noticed that 10 GB of data had been consumed within just two days, even though I had not used my line in a way that would justify such high data consumption. When I called customer service about this, I was told that, because I was using an internet hotspot, they could not see what content was consuming my data. Even if they cannot see the exact content, no technical investigation or alternative solution was offered, and my request to speak with an authorized person was not properly handled. The representative kept repeating the same explanation, then said I would be transferred; instead, I was left waiting for over five minutes with no response. I am constantly told that I am right, but no action is taken and no real solution is offered, which I do not accept as proper customer service. On top of the recurring service problems and unexplained data usage, when I consider switching to another operator, I am confronted with early termination fees that are almost two to three times my monthly bill. In other words, I am paying for a service that does not work properly and at the same time I am discouraged from leaving through excessive cancellation fees. This complaint concerns my Turkcell line with the number 5425273***. I request a detailed technical investigation and a permanent solution to the mobile internet connectivity issues I have been experiencing, as well as an investigation into the unexplained consumption of 10 GB within two days. I expect a clear explanation of the results and, if there is any error, unfairness or technical problem on Turkcell’s side, I expect the necessary corrections and compensation to be made. In addition, I request full transparency regarding how my early termination fee is calculated and a review of this fee in light of the ongoing service issues. I am paying ₺1,150 every month and I expect accountability, a reliable service and effective customer support, not generic responses and repeated excuses.