"Access to the GP Practice"

My father is registered with Coatbank Medical Practice and has been trying to get through on the phone for several days.  

He is suffering from chronic back pain (history of back pain, disc removed several years ago therefore prone to back problems), significantly affecting his mobility and is at risk of falling and potentially further harm as a result.   He has been unable to leave the house for approx. 2 weeks as he cannot walk any distance and has "borrowed" my mum's walking stick to provide some support to stand up and walk around the house.  

I have tried to get through to the practice by phone this afternoon on my dad's behalf (constantly redialing on my mobile), however keep getting the engaged tone.   I understand completely the volume of calls the practice will receive, however I don't think it's acceptable to be constantly getting an engaged tone.   Should a practice this size not have a modern telephone system that advises the patient that the practice staff are dealing with a high volume of calls and they are (number......) in the queue?

The practice website asks patients to listen carefully to the phone options that you will hear, but we can't hear them, just the engaged tone.   If patients have such difficulty accessing the practice by phone, there is a risk they will  either deteriorate and end up in hospital or go elsewhere for  help,     when the most appropriate person  for them to see was their GP.    

Meantime, I am trying to register my dad for the practice "attend anywhere" system and I have  referred him to the NHS Lanarkshire Falls Team in the hope that he can get the support he needs  to prevent him deteriorating  further.