We tried again on Sunday night and the same thing was happening so we left it again until this evening. Same thing today too

I took a video of it and posted on youtube - this is turning the box on, see the lights lighting up, screen all working, etc. Stuck on Waking Up screen. I went close up to the box and you can hear it whirring and making strange noises as though it's trying to do something. The remote does absolutely nothing whilst it's in this state.
It's a Huawei box and the instruction manual says that to factory reset you have to use the TalkTalk button to get into the main menu, but I can't even get off the Waking Up screen and into any types of menu, it just seizes up and makes noises.
We phoned TalkTalk this evening and the rep on the phone was pretty useless, asking if we had the box turned on, were the leads connected, was our tv working, did the remote have batteries in it, had we damaged the box, etc.
Eventually they said they would book us an engineer but we may be charged £75 for this call out and could end up having to buy a new box for another £299 if it was deemed that we had broken it! We haven't done anything at all to it, it just stopped working.
Has anyone else experienced this type of problem with their box, is there a way to reset it, will I likely be charged for it?