"Shocked to receive parking fine"

Hi, i have just received a parking fine for £100 for waiting in my car in short stay car park on the 1st December, 18 min in car park from 22:07 to 22:25. My daughter works at The Urgent Care Centre - 12 hour shift and have been collecting her from this car park. I didnt leave the car and had no idea I couldn't stay and wait for her - although she finishes at 10pm, it sometimes run late and have to wait longer - I am so upset as the car park is empty at this time and I dont take someone place.