Sub standard assistance and weak internet

I have been struggling since the beginning of June with my wifi and LAN connection. I pay full price but receive useless wifi and the technicians / service agents are not able to find the problem. They visited my house as well and provided me with their router. My two routers were faulty according to them. I have been loggin faults daily, but they do not sort it out. I have called their offices a few times as well, but nothing seems to happen. When asking what the internet issue is, they just say that they are not sure / they did tests etc and seems to be fine. Before June, everything was perfect as smooth running. I tried all other means to resolve this issue, but I do not get it. This was my last resort to write a review on this platform. I requested that a manager or senior staff member contact me to discuss this as well, but did not receive any calls / emails or feedback. I do not feel it is reasonable for me to be paying my full subscription fee every month and receiving this kind of service.