You can reach the support chats of the respective CAs via the following links.
CAs support will assist you with technical issues or questions regarding the issuance and verification of outstanding SSL Certificate orders.

DigiCert

https://digicert.secure.force.com/chat/apex/DigiCert_Legacy_PreChat_Questionnaire

Thawte

https://digicert.secure.force.com/chat/apex/Thawte_PreChat_Form

GeoTrust

https://digicert.secure.force.com/chat/apex/GeoTrust_PreChat_Form

RapidSSL

https://digicert.secure.force.com/chat/apex/RapidSSL_PreChat_Form

Comodo/Sectigo

https://support.comodo.com/

https://sectigo.com/support

GlobalSign

https://www.globalsign.com/en/company/contact/