Question on scamming

So, I had a friend that had their facebook account compromised along with Instagram. The person we will call - the a$$, posted a bunch of items on facebook for sale. Unfortunately, the timing for the a$$ was perfect as my friend was out camping without cell service. By the time we reached him, a few of the less tech savvy people had contact this friend. The managed to get a couple emails and a phone number. Now, the thing is two different emails were given out. Also, they called the one person to setup/help setup a Zelle account.

My question is, how could the a$$ use someone else's phone number? When the friend reached out to the phone number given, they played dumb. Now, it could have been an act, but the multiple email addresses that do not come back to the same person as the phone number make it confusing. Can anyone shed light on how this was done?

As an aside, the friend was able to recover their facebook account and locked their instagram account. They now use multi-factor authentication. And, no, none of their email or banking information was compromised - and they have changed those passwords as well. I am trying to understand the scam here. I don't see the pattern in the use of emails and the phone number. Any help understanding it is appreciated.