Phone call stating hacking within my iCloud account, not to use my iCloud user and not to purchase anything in device due to suspicious activity

I keep getting a phone call in my phone since Thursday and it’s not an 800 number it’s a random number with an automated voice saying their had been some suspicious activity on my iCloud account and not to use any device associated with my icloud account and not to purchase anything using my device. I hung up the first time, the second time I ignored it and contacted customer support but they didn’t see anything on their end. I got a phone call yesterday and this time I listened to the end, and it gave me an 855 number to call back. I can’t remember the rest of the number. Could this be legit? Or should I contact customer support? Or should I just ignore the call?