Bad Time Management

I made an appointment at Dis-Chem Boksburg for my nails. As I was waiting for the Nail technician to finish up with her client. I asked at 10h15 how long must I wait as my appointment is at 10h00, I saw that she is not nearly done, I feel that if i made an appointment for a certain time, it should be on that time. This us highly unproffesional. I canceled my appointment. If I was waiting the next client after me would've also waited. I complaint at the manager, and she did appologise, but this is bad service, as I also had other places to be. Bad time management.