Phone Number Validation for WooCommerce

My clients site gets targeted by credit card thieves trying to validate stolen cards. They use fake phone numbers to make an order. Right now this plugin slowed them down, but they’ve just started using sequential valid numbers e.g. +61 8 1234 5678 and +61 8 9876 5432. I’d like to block these two numbers and potentially others or ideally I’d like to add my own regex validator to only allow mobile numbers for Australia e.g. +61 4** *** ***.