Had issues with our boiler since it was installed. We rent. The boiler was installed by some guys, they failed to register the warranty, it started going off at random times. Nothing fixed it. Someone was meant to come in November from manufacturer and didn't. We had Covid so never got round to chasing it although agency were aware it still didn't work. Anyway from around 27th dec it's been making this horrid noise which has got worse and now it's not heating the radiators at all. Is this an emergency or should I wait until Tuesday?