Locking up and just leaving children outside gym

On Saturday, 5th September: My 2 daughters, 11 and 14 year old came to the gym and arrived at around 6h45pm on Saturday evening. I did not actually realise the closing time on a Sat as we had never been on a Saturday evening. The lights in the gym were still on and there were still cars parked around there. I went home and received a frantic call from my daughter saying the club had closed at 7 and the man that locked up had abruptly said they close at 7, locked up and left whilst the girls looked on at him leave. They were on their way to the Pick 'n Pay when they were approached by 4 drunk men who wanted their phones and bags... they thankfully ran the opposite direction through the parking lot towards the Pick 'n Pay. When I got there they were thankfully safe at the Pick 'n Pay however the men seemed to have followed them and were at Andiccio. I should have checked 100% at what time the club closed, however believe that if this person took any notice he would have known it was error and surely would have helped if he was anything half human. Horrified that Happy called however no follow up since then.