Pathetic and no regard for senior citizens

I booked a ticket yesterday for my parents.I sent an email requesting a wheel chair as my parents can not walk much of a distance.My father has a heart Condition and my mother had an operation not long ago.The agent tells me I was supposed to request this 3 days ago.How do you request 3 days ago when I only booked the tickets a day before departure as it was last minute travel arrangements. THEIR SERVICE IS HIRRIBLE AND SHOULD SOMETHING HAPPEN TO MY PARENTS I WILL HOLD THEM ACCOUNTABLE