Send back proof of payment to the state in response to their notice.  

Thank you for your help. I tried to call their provided phone number nearly 10 times but could not reach them. The address I saw on the notice is the PO Box address of FTB, is it the right one I should sent my proof?

Thanks again for your time.

Read the notice carefully ... there must be instructions on how to respond if you don't agree.  

And when you send the response letter:

• Include a copy of the letter you received
• As @Critter-3 noted include copies of what ever documentation you have reflecting payment.
  • This may include a screen shot of a CC receipt if this was the method of payment
  • Screen shot of a bank statement reflecting the withdrawal.
• When sending your response letter, make sure you send the letter certified mail return receipt requested.  This is key since it is basically your insurance policy that you timely responded should verification be needed.

Thanks a lot. I followed your guide and sent them all. Hopefully it will work. The notice I received did not have instruction if you don't agree, it just had a phone number and website to pay the owe. Thanks again.