Should I switch providers?

FTM here... It's been impossible to make appointments with my OB. Every time I call they put me on hold for 20 minutes. I didn't have a first appointment until 13 weeks to even confirm the pregnancy. Now they are telling me that their ultrasound tech quit and that I can't book a 20 week appointment until they find a new one. It's three weeks away until I'm 20 weeks. I have been trying to make that appointment for 5 weeks so that I can get the time off work. I feel like they aren't taking care of me in a timely manner at all and I'm worried that I won't get good care during the birth. What do you all think- should I stay with this provider? I'm scared to try and find a new one.