Show only nodes in a view which have the same value of a text field (field_phone_number)
You're on the right track with EVA. To list sibling nodes based on common taxonomy terms or entity reference fields you can just use Views configuration, but if you need to filter based on a different common field EVA is the way to go. 

You did everything right except for the last step - you don't need Content ID Contextual filter, you're not comparing nodes, you're comparing Phone number fields! And the argument you set for EVA is the phone number, so that is the information you need to include there. 

Add a Contextual filter for the phone field, you can configure it:
    When the filter value is NOT available
    Display contents of "No results found"
    When the filter value IS available or a default is provided
    Specify validation criteria
    Numeric (or whatever is applicable in your case)
    Hide view (if it doesn't validate)

That should list all the nodes that share that field, including the node you're currently viewing. 

If you want to exclude the current node from that list you need to add another Contextual filter, this time it will be the Content ID one:
    When the filter value is NOT available
    Provide default value
    Content ID from URL
    When the filter value IS available or a default is provided
    Specify validation criteria
    Content
    [ABC]
    More
    Exclude

That one will exlude the current node from that list.