Service Provider cannot set dual time

I have a Service Provider that have a service duration of 1 1/2 hr. This service provider can work for example:
Monday - at moorning 9-10.30 am - Afternoon 17.30-19.00 pm
Tuesday - at moorning 9-10.30 am - Afternoon 18 - 19.30 pm
Wednesday - at moorning 9-10.30 am - Afternoon 17.30-19.00 pm

How can I set to get this schedule free? Can you help me?
Another issue is when I set reminder email for client, i put 24 hours, and the reminder is sending "2" mails, not 1. I receive 2 mails and I have to receive 1.
Thanks in advance.