"We don't feel it was treated as an emergency"

My mum phoned 999 saying she thought my dad was having a stroke following the FAST questions. He was FAST+ with speech difficulties. The person at the call centre said a nurse would call her back. 20 minutes later no one had called back. We decided not to wait any longer and that she was going to take him to hospital by herself. We phoned back 999 to let them know in case an ambulance was on its way. My mum was told there wasn’t an ambulance coming that the call centre needed to cancel. He went to hospital and a stroke was confirmed. We wanted to feed this back as the FAST campaign says that it is an emergency and to dial 999 for an ambulance yet we don’t feel in this case it was treated as such.