Telephone field

Hello. How is possible that I can send an email only with “5” number in telephone field?
Telephone numers, for Italy, are, for example, in this format: (+39) 123 45 67 899

How can i fix it?

This is code:

<div class="contact-form-style-3">

<p class="col-md-4 cf-style3-name">[text* your-name placeholder akismet:author "Nome e Cognome*"]</p>
<p class="col-md-4 cf-style3-email">[email* your-email placeholder akismet:author_email "Email*"]</p>
<p class="col-md-4 cf-style3-phone">[tel* your-tel placeholder "Telefono*"]</p>
<p class="col-md-12 cf-style3-text">[text* your-subject placeholder "Titolo della richiesta*"]</p>
<p class="col-md-12 cf-style3-textarea">[textarea* your-message placeholder "Messaggio*"]</p>
<p class="col-md-12" >[submit "Invia Messaggio"]</p>
</div>

The page I need help with: [log in to see the link]