Support System - What's the URL from Front End ?

Hi there,

I have a WP Multi Site Install with Pro-Sites activated with Manual Payments.
I wich to give the ability to my clients to contact me by opening a Support Ticket from Pro-Sites Manual Payment page.

However i dont know what is the URL that i need to code in "a href" tag.

How can i do that without forget that what i need is that when the client clik on URL he/she goes to his Site Dashboard on Support Tickets & Not to My Main Site Dashboard ( that they dont have permissions to access ) ?

Thanks for youre help