How can our account be blockd or banned, please answer.

Are you experiencing a blocked account as a stock user? Never heard about that! But you should contact customer care on this. Adobe customer care can be contacted by beginning a secure chat session at https://helpx.adobe.com/contact.html?rghtup=autoOpen. Pop-up blockers need to be disabled! If the chat window fails to open, or is non-responsive, use a different device to start the interaction.
Support phone numbers may be found here: https://helpx.adobe.com/contact/phone.html. Please note that phone charges may apply.

(see also here: https://community.adobe.com/t5/creative-cloud-services/how-to-contact-adobe-support/td-p/11875703 or here
https://community.adobe.com/t5/account-payment-plan/how-to-contact-adobe-support/td-p/11843852)

If you are a contributor, then yes, your contributor account can be blocked for multiple reasons:

• posting assets that are not yours
• excessive sales activities, showing some kind of fraud pattern
• spamming the submission queue 
• submitting inappropriate content
• having submitted massively content that does not meet the required quality (this are mostly older accounts of people, who submitted prior to the stringent vetting that Adobe applies).