I can understand your frustration. It really depends on how busy the Service Center is. I tried calling my local SC (just 2 miles from my house) 8 times over the course of 14 days to get an update on the rear window defroster fix and got to speak to a human twice. If the SC isn't open or too busy to answer the phone, it will route the call to an offsite call center. I learned this after calling the out-of-state Delivery Center where they accidentally sat on my title paperwork; I ended up being routed to someone in Fremont, Ca.
Tesla's service issues start at the top. They've under-delivered in production release dates, production numbers, and early production quality. They rushed both the Model X and Model 3 to boost the delivery count for share price and bond price pressure, then figured the flaws could be corrected at the Service Center (causing a bottleneck in Tesla dense regions). It's also a huge waste of money in parts, labor, and loaner-cars/rental cars to fix production problems post-sale. Had I taken a rental car from my SC, it would have cost them about $560 in rental fees (I assume the rear window defroster fix was either a relay, fuse, soldering job, or software...the glass wasn't replaced). Furthermore, the car sat for 4 days before they did a diagnosis and another 9 days before they moved into the service bay for the actual repair. I wish they would have just told me that they were backlogged and wouldn't have time to look at the car until days after the scheduled appointment.
Secondly, the proliferation of the Model 3 is also inundating SCs with more volume based on the sheer population of more owners. Thirdly, in this economy of record-low unemployment, it is a struggle to find affordable competent talent. The job market is good where good employees are tempted to chase better compensation (how do you retain them?), and then new hires tend to be less talented/experienced and have to learn the ropes. Working for any company with high turnover is chaotic. Finally, the company is under pressure to cut-costs and pressure from Wall Street is immense. Outflows from institutional longs (Saudi fund, T. Rowe, Fidelity, etc), short sellers pressing their positions, analysts lowering targets, and the narrative of their demise or buyout is popping up.
I would love for Tesla to sort our their processes and procedures to get this company running smoothly. We all love the car and want to company to succeed. I think it's sad that people are betting against the company when the company's vision is for environmental sustainability.