Parking on Jacks Farm Way, E4

I pre-booked this parking space and it was confirmed. Today I drove to Highams Park (58 miles from home) and the plan was for me to park in the space then get into London on the train for an important meeting. I arrived to find the parking space occupied. I could not get any answer from the space owner so I rang JustPark to cancel the booking. I had to find somewhere else to park resulting in a lot of hassle that I was trying to avoid by using Just Park. I suggest that other users avoid this person as they are unreliable and the whole concept of the Just Park app is that we can access reliable parking. The whole experience was a nightmare and it didn't help that I got a message telling me that the space owner had cancelled the booking 28 minutes after the booking had been due to commence and 10 minutes after I cancelled with Just Park. Very unsatisfactory!