Turkcell Superbox Cancellation Fee Shock And Extra Charges Issue

I wanted to cancel my Turkcell Superbox subscription today because I was not satisfied with the service. During my call with customer service, I was told that the early termination fee would be ₺2,300 and that this amount could increase in the coming days. Immediately after confirming the cancellation over the phone, an additional ₺3,500 was added to my bill on top of the ₺1,200 internet fee. After the cancellation, my internet service was completely cut off, and I can no longer use it in any way. My subscriber number is 5373****94, and I used the service for about 40 days. I have not yet returned the device, and I was not given a clear explanation of what the total charges include. When I contacted customer service again, I still could not get any detailed information. I expect Turkcell to clearly explain the additional charges reflected on my bill and to reduce the amount. I request that my grievance be resolved.