How do i stop "olivia from icloud support" to stop calling me

It is a phishing attempt. Apple won't call you unless you ask them to.

Scams (e-mail, text messages, and phone calls) are getting very good at closely imitating true Apple communications. Always be cautious. Here are some guidelines:

Identifying legitimate emails from the iTunes Store - http://support.apple.com/HT201679 - lacking in specifics, the next link is better:

Recognize and avoid phishing messages, phony support calls, and other scams - https://support.apple.com/HT204759

If somebody knew how to do that effectively they would be a millionaire. You could try blocking the number but I suspect they have no shortage of numbers from which to call and they are probably all falsified anyway. You'll just get called again from a different number. I guess you could never answer your phone but have message telling people to call back again immediately from the same number and you will answer it the second time. Many calls are from robots and I find if I continuously speak a greeting lasting about 6 seconds it makes them think they got an answering machine and they hang up.

Block phone numbers, contacts, and emails on your iPhone, iPad, or iPod touch --> https://support.apple.com/HT201229