Superonline Gave Me 6 Mbps Instead of 500 Mbps and Refused a WiFi 6 Modem

Since 2014, I have been a Turkcell Superonline customer. Unfortunately, over the past year, I have experienced extremely negative issues with my internet service. With only two days remaining on my contract, I did not want to go through the trouble of switching to another provider, so I accepted the 500 Mbps high-speed package. However, I later discovered that the modem they provided does not support this speed. I specifically informed the customer representative that new subscribers are being given a WiFi 6 modem and that I also needed one since my current modem does not support the upgraded speed. The representative assured me that my current modem was sufficient for my existing 100 Mbps speed and that if an upgrade was necessary, a modem replacement would be provided. Based on this assurance, I went ahead with the 500 Mbps speed upgrade. Now, my internet connection is highly problematic, with 450 ms ping and only 6 Mbps speed, which is just 1% of what I should be receiving. While the company offers suitable modems to new subscribers, it is unfairly neglecting a loyal customer of 11 years. I urgently request a solution to my speed and connection issues, along with a WiFi 6 modem replacement. I expect immediate action to resolve this matter.