You can check every registered EAC document status on-line following the links below.
(Note: This is Russian national federal register so it doesn't contain the documents issued or organization accredited by Belarus, Kazakhstan, Armenia and Kyrgyzstan)
Accredited organization status
EAC CoC (certificate) status
https://pub.fsa.gov.ru/rss/certificate
EAC DoC and GOST R (Unified) DoC (declaration) status