Hi,
Sorry to hear this. If the box itself is failing then it does need to be replaced by an engineer.
Have they booked this in for you, what date is this arranged for ?
A month is far to long to wait, in my opinion, so I'll see if I can get this done any quicker for you.
I'm not in the office until the morning, but I'll add your details to my watch list and check with the engineer booking system to see what can be done.
Thanks
Karl.