Unfair Demand Letter from Coldwell Banker Real Estate Agency

About three weeks ago, I made an agreement with GO Yatırım Gayrimenkul Ltd. Şti. (212 Shopping Mall Branch), which is a Coldwell Banker agency, about the sale of my 2 + 1 house. During this agreement, I stated that if the sale takes place, I will vacate the house within a minimum of one and a half to two months, and that I will look for 3 + 1 for sale in the meantime. We agreed. Several buyers came to see the house for two weeks, but no result came out. During this time, I was continuing to look for a house. Then a buyer came out who wanted to see the house together with agent. I received a phone call from the real estate agent right after they left the house. He told me on the phone that he had received a deposit and said to start the title deed procedures the very next day. In the meantime, neither the real estate agent nor the buyer and I discussed money or exchanged any money. I didn't even say two words with the buyer except when he came home. I had no communication afterwards. Of course, in this two-week period, I could not find a house suitable for my budget, on the contrary, housing prices increased in parallel with the increase of the dollar. I stated this to him on the phone. The real estate agent said that he would easily find me a house in two months. I told him that there was no guarantee that I would find the house I wanted in the style I wanted, suitable for my budget in such a time, and I told him to return the deposit to buyer and that he could not do this without asking me. Of course, my intention was not to give up the sale. I told them, "Let's suspend the sale advertisement on the well known popular website for now, but don't delete it, let it stay there, I said, when I find a suitable house, let's put it up for sale with you again." I did not cancel the written contract between us. I wanted to suspend it on the website because I could not find the house I wanted, so as not to bother the real estate agent and buyers until I found a house. In this period, I took the utmost care to adhere to the agreement between us. But the interesting and ugly event appeared by demand letter that came to my door the day before (on 2.08.2023). In demand letter, they stated that 318.600,00 TL, 4% + VAT as a withdrawal fee, should be sent to their IBAN address, otherwise the legal process would be initiated. This approach is totally unacceptable and ugly in terms of both humanitarian and business ethics.