Very unhappy client

I was hospitalized on the 29th of June due to a kidney stone that was blocked in my ureter, hospital got authorization for procedure, due to pandemic, they could only do the surgery on the 1st of July because they had to wait for my covid results 1st before they could proceed with the procedure, i received a medical bill that Discovery will only pay 70% of the bill, because it was an unplanned emergency, i just want to know, if they say they cover emergencies 100%, how come I have to pay a huge bill now, and also how do you plan an emergency? You can’t, that’s why it’s called an emergency for a reason.