Turkcell 12 Month Subscription Same Day Cancellation Fee Dispute

Today at around 3 p.m., I accepted a 12‑month subscription offered to me in a phone call from Turkcell for my iPhone 12 postpaid line. A few hours later, at around 8 p.m. on the same day, I decided to cancel this subscription because I found a more suitable offer from another operator and I had only been within this new commitment for about five hours. When I contacted Turkcell customer service to cancel, I was informed that I would have to pay a withdrawal/cancellation fee of approximately ₺659, even though I had used the new subscription for only a very short period of time on the same day. I find it unfair and disproportionate to be charged such a high fee for something that was activated and cancelled within a few hours. In this context, I request that my 12‑month subscription be cancelled without any withdrawal fee being charged, or alternatively that the subscription price be reduced or a more reasonable solution be offered so that I am not financially penalized for a decision I changed within the same day.