Absolutely horrified

We booked flights for my mother to fly to dbn with my 5 year old little girl. Needless to say when travelling with a child she was a little late. We arrived at the check in counter at 4:35 her flight to dbn was to leave at 5:10. On arrival we were greeted by rude unfriendly staff who told us in no uncertain terms that the check in was closed and there were no further flights out for the day. The plane had not left and the gates were not closed but nothing could be done. We then we're sent to the ticket counter to change the dates on the tickets and pay a penalty fee. When arriving at that counter a ride consultant who didn't greet didn't smile and was of no help says that my mother would be on standby all day because her ticket says already flown. We then asked to speak to the supervisor who seemed knowledgeable. She said that my mum and baby would fly out on the first flight in the morning she should arrive early before 6 am. We booked a hotel for her which cost so much only for her to arrive in the morning and be told she is still on standby and there's no seats available. Mango what the heck is going on. Worst experience ever. I want my money back. Theives