Appointment for Installation Issues

I keep getting called by openserve technicians to install my fiber line. I have 3 people living in my house and we all work full time, but the technicians expect me to drop everything at work and go immediately to open up for them. This is the third time I've been phoned and when I give them a time and date they won't commit because it's not when they want to come and a few days later another technician phones me. Do they not understand how to schedule something? The last woman who phoned me said she'd make a booking for 12:30 tomorrow but I seriously don't know if she'll even come or if I'll just get another phone call at 11 tomorrow morning while I'm at work with them wanting to come at 11:30.