My Turkcell Network Is Not Working

I live in Tokat/Turhal, right in the city center. However, neither Instagram nor Youtube.com works with my Turkcell line. I have to wait 2 minutes for the page to open. It has become almost impossible to watch videos, send messages or even use the internet. Unbelievable, but I even had a hard time accessing the Xolvie website. I waited for minutes for the page to load in order to write this complaint. We contacted customer service twice and they told me to turn off my phone and they updated it, but the complaint continues. I am not looking for this error in my device because I never had such a problem when I was using another operator. Therefore, I am sure that the problem is completely caused by the Turkcell network. I had previously switched from another operator to Turkcell, but after what I experienced, I am seriously considering switching operators again. It is impossible for me to continue with such poor reception quality and internet service. I demand that what is necessary be done urgently!