As your router is powered up you will get WiFi as it is your Access Point for your wirless devices to connect to the Internet, connecting to your router by WiFi does not prove or disprove that your devices will connect to the Internet.
I am assuming that you have the white Sky router (SR213), if you have a blinking green light then it is attempting to make a connection to the network. Once connected it goes solid white.
If you are on Fibre - you will also have an ONT which is either a small white box (Openreach) or a small back box (City Fibre) attached to a wall next to where your fibre comes to your house. Check that this is powered up and you have a PON light and no red lights. Assuming this is all OK, check that the ethernet cable that comes from the socket on the ONT goes to the WAN socket on the back of your router, this must be plugged into the WAN socket, it will fit in others but only the WAN socket will work. It is the right hand most yellow socket on the back of your router, when looked at the back.
If you are on ADSL, make sure that the cable from the phone socket on your wall is plugged into the purple socket on the back of the router, it will fit into any of the sockets, but it must only be plugged into the purple one.
Start there, if still no good you may need to call Sky.
--
I remember the Internet starting!
Sky Full Fibre & Virgin Media XGS-PON, with automatic failover using DrayTek multi WAN router.
Sky Q, which will be sadly missed when they decide to kill it off!
