Turkcell Superonline Failed to Provide Stable 1000 Mbps Internet Despite Multiple Fixes

I have a Turkcell Superonline 1000 Mbps internet subscription. For the past 10 days, I’ve been experiencing constant disconnections and download speeds measured in kilobytes. I’ve repeatedly called customer service, and online troubleshooting was attempted but didn’t work. A technician came to my home and replaced my modem with a newer model. For three minutes, I received the speed I’m supposed to get, but it went back to the same issue afterward. I’m at a loss for what to do. With wireless connections, the speed is measured in kilobytes, and even when I use the 1-meter cable provided by the service, it doesn’t exceed 35 Mbps—far below what I’m paying for. Thinking the issue might be my computer, I formatted it three times, installed two different operating systems, applied all updates, and downloaded drivers directly from the manufacturers’ websites, but my internet speed is still slow. When I explained my frustration to customer service, they mockingly offered me 4 GB of daily mobile internet if I use a Turkcell line. I should already be able to download that much data in 10 seconds with my fiber internet! This is nothing but a joke. They’ve left me no choice but to cancel my subscription, but as of December 22, 2024, at 01:29 AM, they quoted me a cancellation fee of over ₺4600. I don’t know what to do. I urgently need internet, but it’s just not there.