Garanti BBVA's Unethical Return Policies!

I was planning to get a refund for the digital piano I purchased on N11 with my Garanti BBVA credit card. However, with a really unethical idea, they are trying to turn the customer's money inside and use it like an interest machine. I bought the product in installments for a total of 6 months. I paid the first installment of the product I returned on the statement cut-off date, but now that the return of the product has arrived, the first installment I paid is not reflected. Some of the customer service representatives I've spoken to say, "It will be refunded in the last statement," while others say, "Because you paid one month of the installment, it will come with a delay of one month." Another says, "All of them will be refunded with a one-month delay, in the last statement, the first installment you paid will be refunded," and so on. It's evident that the logic is flawed. If I hadn't paid my statement on time, you would have refunded every penny. But do you receive a statement from me a month late? Since you don't, then there is a serious logic problem that even a logician cannot solve. Or, in short, there is an evident ulterior motive, and everyone who reads this article understands what that motive is, so I won't write it down. The inflation rate in this country is obvious; I don't even keep my money worth ₺200 in TL, and no one does. You're talking about returning my money of ₺5000 after almost 5 months. Excuse me, will I buy a drinker with my own ₺5000 money after 5 months? Additionally, in installment return transactions, when you return a product purchased in 6 months installments worth ₺30,000; the 1st Installment ₺5000, 2nd Installment ₺5000..., 6th Installment ₺5000 appears on the statement, and ₺30,000 is deducted from the credit card. However, what you're doing is not a refund. You're telling me that I will be refunded month by month, and this takes up ₺30,000 on my credit card, in addition to all these dissatisfactions. I have never seen or heard of such a disgrace and such unethical actions before. It requires a great deal of trust to even attempt such a thing, let alone do it to a customer. In no longer than three working days (because my money is melting), I want the first statement I paid to be refunded correctly, and the remaining refund to be made accurately, and the credit card to be emptied as it should be. Otherwise, I will cancel my account and use all my rights on the subject.