Custom field with phone format

I created a custom field for a phone number and applied the phone number format “Phone # (10 digits w/ possible hyphens, spaces, brackets)”. This format doesn’t do anything and it might as well be a text format. If someone enters 10 digits without the hyphens or spaces, the system interprets this as a date. This causes issues when using the Member List short code. Is there any way to enforce the phone number format of dashes between the numbers?