i forget my security question and i cannot reset it

You will need to speak to account security about that.

If you forgot the answers to your Apple ID security questions -

https://support.apple.com/en-us/HT201485

Apple ID Support -

https://support.apple.com/apple-id

World-wide Apple Support -

https://support.apple.com/en-us/HT204169

Support by phone, email or chat -

https://getsupport.apple.com/

Apple Support by Twitter -

https://twitter.com/AppleSupport

iTunes Support form -

https://support.apple.com/en-euro/itunes-contact

ASC - Late 2012 Mac mini, macOS 10.15.5; Watch, series 5 GPS/cellular, watchOS 6.2; iPad Air 2, ipadOS 13.5.1; iPhone 8+, iOS 13.5.1; TV 4th Gen, tvOS 13.4.6;  HomePods, audioOS 13.4.6 and Airport Express w/ Airplay 2

See If you forgot the answers to your Apple ID security questions https://support.apple.com/en-us/HT201485

You have indicated that you can't answer your security questions satisfactorily. So see Security and your Apple ID https://support.apple.com/en-us/HT201303

This document says “without proof of your identity via security questions and other carefully selected criteria, Apple Support can't help you reset a password or perform any other actions on your account.”

Thus, we can do nothing to help you, except to mention that Apple support might help you if you have an extenuating circumstance (e.g., you have your receipt for your purchase of a pertinent device from an authorized Apple seller with its serial number on it). If you want to contact Apple Support to discuss any possible extenuating circumstance, see the support options below. Alternatively, if an Apple Store is open in your area, then you can go there to deal with your extenuating circumstance. You also can make a genius-bar appointment (https://www.apple.com/retail/geniusbar/) if you want.

Get a call from Apple support to help solve your problem using this link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362

Apple ID Support https://support.apple.com/apple-id

Apple ID account security for country-specific and region-specific help https://support.apple.com/en-us/HT204169

Get Support: We’re here to help https://getsupport.apple.com/. Go through the options to find the best support option.