Hello jesuscomingsoon,
You should be able to mark unwanted email as junk using the steps below:
• On your iPhone or iPad, swipe left on the message, tap More, then tap Move to Junk.
• On your Mac, select the message and click the Junk button in the Mail toolbar. Or you can drag the message to the Junk folder in the sidebar.
• On iCloud.com, select the message, then click the Flag button and choose Move to Junk. Or you can drag the message to the Junk folder in the sidebar.
You can also find those steps in this resource: Report and reduce spam in iCloud Mail - Apple Support
Additionally, are you seeing those unexpected contacts in the built-in Messages app, or is this happening with a third party app such as Facebook Messenger?
Let us know, and we'll keep moving forward from there.