Turkcell Prepaid Plan Button Switched My Line to a Postpaid Plan Without My Consent

I have been using my Turkcell line as a prepaid (Hazırkart) subscriber for years. On 16 October 2026, shortly after midnight at around 00:30, I entered the “Prepaid Plan Packages” section in the Turkcell mobile application and tapped on a 10 GB internet package listed there. When the process finished, a “Welcome to the Billed Plan” screen appeared and I realized that my line had been switched to postpaid without my explicit consent. Moreover, an automatic bill payment order had been defined through VakıfBank without my knowledge. A button displayed under the heading “Prepaid Plan Packages” changing the subscription type in one step, without any clear warning or separate confirmation that the line will be converted to postpaid, is misleading and unacceptable. After this incident, I saw on my account screen that my line is now shown as postpaid and that a package called “Bol Star Fırsat 10 GB” has been assigned. This shows that the button I clicked in the prepaid section directly moved me to this postpaid package and postpaid subscription. There was no explicit information on the screen that my line would be switched to postpaid, nor was there an additional approval step. I also noticed that an automatic bill payment order had been created via VakıfBank even though I did not request such an instruction. On the same night, between 01:00 and 02:00, I called the call center and explained that this transaction had been carried out without my consent and through a misleading flow. I was told that I would have to stay on postpaid for one month to return to prepaid, and that they could not cancel the automatic payment instruction. In other words, I am being asked to remain on a subscription plan that was created without my explicit approval in order to undo it. I then submitted a written request to Turkcell with the number 201669392 and also filed a complaint with BTK under the number 325715696. Turkcell’s own system records clearly show that the transaction was made via the mobile application and through which menu it was initiated. My expectation is that my line should immediately be converted back to prepaid (Hazırkart) without any waiting period, that any commitment which may have been defined under this postpaid package should be cancelled without a termination fee, that the automatic bill payment order via VakıfBank should be removed by Turkcell, and that all charges to be issued for the postpaid period should be cancelled and refunded if any payment has already been collected. There are many similar complaints about the same flow, which indicates that this is not an individual mistake but a design problem in the application interface. I request that this misleading process be corrected and that my grievance be fully resolved.