Well take the 24th for example, they billed you for 12kWh, they claim you used 38kWh (before solar), and you produced 35kWh. So in my eyes you used 38kWh, and produce 35kWh, meaning you have a 3kWh deficit, but they are billing you for 12kWh, or 9kWh more than you actually used.
This 9kWh might be from discrepancies in your equipment or their meter. Only way to find out is to verify yourself. If the discrepancy is on their end, I would assume they are responsible to get it fixed ASAP. But if your inverter claims it brought in 35kWh, and after 90% efficiency of converting to AC and sending it back, that is 31.5kWh. We're getting closer.
Now, if your Solar Agreement stated that they would only give you credits for 70% of what you used, then you are just SOL.