Hey
This is truly a Wix Code question but it is also very simple to answer and you do not need to code to make this happen.
When you have a page on your site which is restricted to members only and you have placed a form on that page using 1) A Dataset 2) Input fields from User Input Area in Wix Editor 3) A submit button connected to the Datasets Submit action — All records stored will have the _owner field populated with the logged in users id.
So on the page where you want to show phone numbers added by the logged in user just add a Dataset and click Manage Dataset, scroll down to Filters and Add a filter. Set the field _owner to “Logged in user” and voila. This will filter out all records created by that logged in user.