I just received an automated call stating that there was suspicious activity on mi iCloud account and telling me not to use any of my apple devices until I contact apple support. Is this a legitimate call?

It is not a legitimate call.

Apple does not make such calls.

All such calls are scams from criminals attempting to steal your personal and financial information. The callers will often use number spoofing to pretend they are calling from a legitimate business. The correct course of action is to ignore the calls or hang up on them, repeatedly if needed. 

Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support

I have already received 9 calls this morning and early afternoon, it is Sunday by the way. I answered the 2nd call it was automated so I followed through, this is what I prefer to do, see how the scam is played out. It went like this: The automated system represents themselves robotically as ‘Apple support’ saying, “Your iCloud has been breached. please hold while we connect you to a representative” All sorts of static and noise in the background and, on my call, a man with a very thick Eastern accent picked up and requested my name. I very firmly responded, “Beg your pardon? YOU. Called ME. Why should I tell you my name?!” He abruptly disconnected up the call. However, the calls have continued every 30 minutes since then, regardless of blocking the numbers.

It’s more of a pain in the neck and terrifying for the innocent.