Hi ribo
You can update the link tag for these phone + mobile numbers via the file: /templates/ja_fit/html/com_contact/contact/default_address.php
I attach this file here for sample, in which I updated these lines:
<span class="fa fa-phone"></span><a href="tel:<?php echo nl2br($this->contact->telephone); ?>"><?php echo nl2br($this->contact->telephone); ?></a>
<span class="fa fa-phone-square"></span><a href="tel:<?php echo nl2br($this->contact->mobile); ?>"><?php echo nl2br($this->contact->mobile); ?></a>