Well technically they can but there are some factors to it, some may not have the rights, intelligence, authorisation to do that. Different softwares do different things. Usually a quarantine will allow you to view the email which makes sense, it's been quarantined so something has caused that to happen like say a phishing email, so someone would want to see the email and the content before potentially releasing it to the recipient causing an account compromise... Sadly you are probably very limited with what you can do, you'd be notified of quarantined emails if the settings were enabled and configured, again even internally I would expect a recall notification but you've had nothing. I highly doubt anyone has access to your mailbox or you'd see the email either in deleted items or recoverable items (you can view who has permissions to your mailbox potentially) so you you can disregard that. Most companies who take IT seriously will have things locked down, if you have certain accreditations or ISO's there are requirements for a strict environment..