Morning again,
So, as I see now, nothing has been fixed. All the issues I had before are back in less than 3 hours. I waited 24 hrs hoping that the connection would stabilize, but it's already clear that is not. At first, the speed began to drop and then disconnections so I had to restart the router again every time. I really don't know what is going on, but there must be something else... Maybe I need to replace the router? The engineer said it's old and it really is. I've had it for almost 10 years. But anyway he didn't say this is what is causing problem. The speed doesn't exceed 10 Mbps to the devices and 30 Mbps to the router. This is not what guaranteed.
