Sunrun review: Billing, customer service, and system failure 1

I have been with this company since before they changed from Vivint to Sunrun. I never really had problems besides the constant equipment malfunctions. This would cause issues with the utility company, but the issue would always be resolved, and my billing was never affected. In December, I received a bill of $808.24 because I had supposedly produced over 4,000 kWh of electricity. From my utility company, I received two bills of over $230. For reference, for the past four years, I have never used more than 700kwh, and I have never paid over $180 to Sunrun and $15 to my utility company. This is on a busy month like December when I use more energy than most months. I made a mistake and called customer service. They told me they would look into it and that I should receive reimbursement. The next billing cycle came up, and nothing was done. I called again, another mistake, and they said that Sunrun is responsible since it was a mistake on their part and that they will be reimbursing me for the overcharge by Sunrun and my utility company. I was in contact with a total of 4 people who told me I would be receiving reimbursement. Finally, they opened a case for me with the case manager, who said the billing was correct, and they sent me a report of the energy I used that year and the invoice for that month with no further explanation. It shows in the report that I used 600kwh in the month of December. I contacted customer service again, and they said they would call me. They opened the case again and, over the call, said they would reimburse me for the overcharge by Sunrun and my utility company. However, this never happened, and I got in contact with them again, this time they said that the billing was correct because, due to the equipment failure, they did not accurately read the actual amount of energy used and that from March until November, I had produced more energy than was recorded on the invoice. That means they undercharged me almost $700, which I now owe. They would only put in writing when they would decline the reimbursement but call when they would agree to reimburse me. I had to use what I got from them, which was the energy report they sent me of what I actually used for those months. I compared them to what the invoices said, and they were right; I produced a bit more than what was on the invoice. I added it and compared it to the rate they charge for each kWh. I owed about $217. So about a $480 overcharge from Sunrun plus the $485 I overpaid on my utility bill, I was now paying about $965 more than I actually owed. This is what was my understanding of the situation. Once again, they did not explain the issue but instead sent me documents and said they confirmed the overcharge. If Sunrun could train its customer service employees to give more accurate information and have case managers take the time to look into the issue and properly explain it, that would be extremely helpful. It would make it feel like less of a scam. My advice to those looking into getting Sunrun, get everything in writing. My biggest mistake was calling them. Everything, and I mean everything, needs to be in writing, or they will have you going around in circles and wasting so much time and money.