Turkcell Network Issue - I Want Proper Solution

In a place like Demetevler in Yenimahalle, Ankara, I can't get any signal or internet inside my shop. I called twice and reported the issue—they said they would provide support. However, I later received a negative response via message. I'm a Platinum customer and have been using Turkcell for years, but I’m now considering switching providers. Due to my work, I need my phone and internet to be active at all times. I expect assistance and a proper solution.