Late payment penalties for California state taxes: The penalty is 5% of the unpaid tax, plus 0.5% of the unpaid tax for each month (or part of a month) that the delinquent tax goes unpaid. The maximum penalty is 25% of the tax not paid. If you file a late return and make a late payment, your penalty will not exceed 10% of the amount of tax due. If you cannot pay your balance owing, you should still file on time to avoid being charged the late-filing penalty. The late-filing penalty is 5% of your balance owing, plus an additional 1% for each full month that you file after the due date, to a maximum of 12 months. -- from Bing Search on "penalty on late payment of taxes california" More on reddit.com

Did your $1505 payment clear your bank account? If so, mail the $140 with a letter that your previously paid and it cleared your bank on xx date. Include a copy of the notice you received. Put your phone number in the letter. Keep a copy of the letter. More on reddit.com

The Franchise Tax Board is the agency that handles California state income taxes for everyone -- including individuals. If you live or work in California and file a state income tax return, you file it with the FTB. So when you filed your 2023 California tax return, did you authorize a direct debit of $2,000? Or do you owe back taxes? More on reddit.com

You should be able to reply to the letter in writing, include a copy of the letter they sent you, the tax return (CA568) the proof of payment and the confirmation. Send certified return receipt it to the address in the letter and keep all originals. They'll process it or send a response probably faster than you can get through the phones. I work with a municipality that follows the CA system of operations and I know why you can't get through. After tax filling season, once everything is entered and imaged, the system is set to non-filer season mode and will start automatically generating letters to every account that doesnt have a proper tax form (for you that's CA568) entered. These letters are generated, printed, stuffed in envelopes, sealed, stamped, and mailed all automatically. Unfortunately, this happens all at once. Meaning thousands of letters go out at one time which massively overloads the people who answer the phones. For perspective, my municipality is 600,000 people and we sent 9000 non-filler letters which we expect 29 people to answer the phones for. Since this is modeled after the CA system (60ish times the size) you can do the math on what CA is facing. We expect to be caught up by Oct. 1. More on reddit.com