Help re boiler

Hi I am looking for some advice I have had a problem with my boiler for a while its a long story so here goes the central heating was stuck on full it would not turn down at thermostat nor off at timer, the boiler is under warranty so we called them up and they got someone out yesterday morning the engineer said it was the valve on the pump which was stuck on the on position therefore would not stop the hot water flowing to the radiators, this was not covered by the warranty which was fine we know a gas man who could come last night and replace this for us

we went out yesterday for an hour and when we got back the house was freezing the radiators completely off called company back who advised all to do with valve and that it had now turned and was stuck on the off position still nothing they would do ok gave them the benefit of the doubt but told them if guy came out and this wasn't the case would they get someone out last night yes they told us open until 8.

Guy came out and changed valve still not working he went to try and check the boiler but the man who had been out earlier had broken one of the screws and it wouldn't come off obviously he wouldn't mess with it because of the guarantee husband tried to phone them and guess what they were shut.

Phoned this morning and they said they can't get anyone out until tomorrow which would be ok if it was just myself and my husband but we have a 4 day old baby in the house and obvioulsly are not able to stay there as it is baltic.

Does anyone know if they need to get someone out sooner? anyone have any ideas what could be wrong with it?

Sorry for the massive story but I dont know what else to do
thanks