disable the charges by user roles

Because these roles are not standard woocommerce roles this option is not available. You will need some customization with your wholesaler plugin to implement something like this.
What wholesaler plugin are you using?

thank you for you’re response. ??

by the way the plugin i used is
Paid Membership Pro. https://www.paidmembershipspro.com

you have any idea on how to work with this ? thank you

You should ask the developer of the premium plugin if he can customise the plugin to read the roles at the checkout page and then add or remove charges based on the role.

i think this plugin is the one that can’t read user roles. ??
please advice thanks

All plugins in www.remarpro.com are free software. This means that everyone can see the source code and implement new features.
You can implement this feature and submit it to https://github.com/mcguffin/woocommerce-payforpayment for approval.

After

$cost = round($cost,2);

you can add
global $current_user;
if ( is_user_logged_in() ) {
if(in_array(‘distributor’,$current_user->roles))
{$cost=0;}
}