Power out in only our flat, management gone till Monday (UK)

This week our building got a new management company. The app we previously used to file complaints has been shut down and our old after hours contact no longer has access to the building. A few hours ago the power went out in our connected rooms and kitchen. The rest of the building still has power, only our connected flats don't. Tried flipping the breaker we have access to and no dice. We've messaged the building manager directly but he hasn't checked his phone. The management company isn't in till Monday and neither is our front desk reception. Between the 5 of us we have 3 small fridges and a freezer full of food that will probably be trash in half a day.

What's the best option here? We've contacted everyone we have access to. Our next step would be maybe an electrician? But the fuse box is locked, they wouldn't be able to access it. Maybe the fire department for a non emergency call? I'm out of my depth here, what are the next steps we should be taking?

(Also I have double checked our lease agreement and access to electricity is indeed part of our tenant rights, with no given exceptions. If that matters)