Router trouble

I had a neotel system installed at my house. Since 2 days later i had problems with the router. It keeps dropping the devices. The technician came to my house, and keyed in the DNS settings which the installer forgot to do. From there on we had better internet connectivity, but still the router keeps dropping. The technician checked the router, and even tried 2 other Zyxel routers, but it does the same. My friend has the same router as me, and he has endless problems. I want Neotel to bring me another router (Not a zyxel), or I will be forced to cancel the contract. I will go to the Ombudsman if it is necessary.