What do you mean by "restore"?

I believe you're mentioning about reset the router to the factory settings. Right? And, I believe you must be using Innatech/Innacomm router that has similar design to the alcatel-lucent (modem) casing.

First of all, do note that modem and router are two different devices (I am assuming you already know this), so when you say can access to the router's dashboard using default provided IP for the web interface, you already reset the router to its factory settings. It is normal for not having an internet connection after reseting the router since your user credentials erased/deleted. You have to set the router once again using the credentials provided by your ISP and set the wireless settings by yourself, once again. Always keep in the mind that, before reset the router, keep your PPPoE username and password. These two are very important credentials needed when setting up a new router. Hope that answers you mate.

Ya, but the the username & password is stored in your router, not modem...

Please do use rj45 cable to connect to router...

Well, if you're unsure/not a technical person to configure networking device, then do not alter/change any configuration by yourself. If you want to save RM53 from being credited to your next bill, ask any of your friends whose expert/intermediate in IT stuff to configure the router for you. He should be a trusted person since this is very important. You can get your own PPPoE username and password from unifi. Just give them a call, they should provide you with the credentials.

That contractor didn't ask you buy from them but contract never up?!