whmcsCrosterTemplates/account-paymentmethods-billing-contacts.tpl

<div id="innerBillingContactsContainer">
    <label class="form-check form-check-inline billing-contact-0">
        <input
            type="radio"
            class="icheck-button"
            name="billingcontact"
            value="0"
            {if $payMethod->contactType == 'Client' || ($payMethod->contactType === null && $client->billingContactId === 0)}
                checked
            {/if}>
        <strong class="name">{$client->fullName}</strong>
        <span class="address1">{$client->address1}</span>,
        {if $client->address2}<span class="address2">{$client->address2}</span>,{/if}
        <span class="city">{$client->city}</span>,
        <span class="state">{$client->state}</span>,
        <span class="postcode">{$client->postcode}</span>,
        <span class="country">{$client->country}</span>
    </label>
    <br>
    {foreach $client->contacts()->orderBy('firstname', 'asc')->orderBy('lastname', 'asc')->get() as $contact}
        <label class="form-check form-check-inline billing-contact-{$contact->id}">
            <input
                type="radio"
                class="icheck-button"
                name="billingcontact"
                value="{$contact->id}"
                {if $payMethod->contactType == 'Contact' && $contact->id == $payMethod->getContactId()}
                    checked
                {elseif $payMethod->contactType === null && $client->billingContactId > 0}
                    {if $contact->id == $client->billingContactId || $contact->id == $selectedContactId}
                        checked
                    {/if}
                {/if}>
            <strong class="name">{$contact->fullName}</strong>
            <span class="address1">{$contact->address1}</span>,
            {if $contact->address2}<span class="address2">{$contact->address2}</span>,{/if}
            <span class="city">{$contact->city}</span>,
            <span class="state">{$contact->state}</span>,
            <span class="postcode">{$contact->postcode}</span>,
            <span class="country">{$contact->country}</span>
        </label>
        <br>
    {/foreach}
</div>

<script>
jQuery(document).ready(function() {
    jQuery('#innerBillingContactsContainer').find('.icheck-button').iCheck({
        inheritID: true,
        checkboxClass: 'icheckbox_square-blue',
        radioClass: 'iradio_square-blue',
        increaseArea: '20%'
    });
});
</script>