Tel validation issues

Hi,

why alphabetic characters are being accepted in the telephone field and the form is still being submitted without any validation, it means that the validation rules for the telephone field need to be modified to prevent non-numeric inputs.

Note: I am using this plugin for country code: https://www.ads-software.com/plugins/country-phone-field-contact-form-7/
and the tag is generating like this: [phonetext* telephone placeholder “Your telephone number*”]

Please advice