Vodafone New Line Application, Conflicting Information, and Billing Concerns

I applied for a new Vodafone line through online services on October 13, 2023, at 13:45. Subsequently, I received a call from Vodafone stating they have exclusive promotions for new line applications, emphasizing a reduced fee of only ₺30, payable in 12 installments on my monthly bill. Curious about this offer, I inquired at a Vodafone store and was informed that the standard cost for a new line is ₺400, but they do allow customers to divide this amount into 12 installments, whether acquired in-store or online. When I mentioned this to the Vodafone representative who contacted me through online services, they insisted there was no new line fee and reiterated the details of the supposed promotion. I expressed my concern about the discrepancy and clarified that if my bills exceeded the agreed amount, I would file a complaint. The representative assured me that our conversations were recorded and mentioned that my monthly charges, including the ₺138 tariff fee, a ₺10 radio tax, and the ₺30 installment, would not exceed ₺150 or ₺155. However, I now observe the new line fee reflecting on my bill. I request immediate resolution to rectify this discrepancy and address the financial implications on my invoice.