@Gemmamiller if the lights onntge the hub show it is not connected run the Service Checker in the My Sky app using a mobile connection to see if Sky are aware of an issue affecting your line. If they aren't call them so they can get it checked out.
Poor wifi upstairs is almost certainly a separate issue as poorWiFi coverage is probably the most common question we get in the forum. In many homes a single Sky hub cannot provide a usable wifi signal in every room due to the layout and type of construction of the property especially in older homes. Assuming the hub is in the best possible position which is out in the open on a surfsce then the only answer is additional wifi sources.
Your choice.is to either buy Sky's add-on WiFi Max bundle which can supply up to 3 extenders see https://www.sky.com/help/articles/sky-wifi-max or buy your own wifi system and use that instead of the Sky hub's WiFi.
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65inch Sky Glass, 3 Sky Streaming Pucks, Sky Ultrafast + and Sky SR213(white Wifi Max hub) main Wifi from 3 TP-Link Deco M4 units in access point mode
