"Why don't they answer the telephone?"

Anything else?

I have been referred for an appointment in the Cardiology Department. I am unable to attend the appointment I have been given. The letter gives me a number to call to change the appointment. I have been calling for two days to change the appointment, and not once has the telephone been answered. This morning, I rang for an hour consistently, and the call was not taken. What am I to do? Nobody is available to advise me.