I cannot see the WHOIS ID Protection TAB on the Contact Management Page
You need to activate the "ID Protection" feature for the domain tld in WHMCS.
Goto Setup -> Addon Modules -> ResellerClub Mods Console and activate "Whois ID Protection".
Goto Setup -> Domain Pricing and tick the box "ID Protection" for each of the domain tld's you want to offer ID Protection.
If you have domains registered before you have activated this feature, then you need to activate this for each domain manually under the clients domain tab by ticking the box "Management Tools" -> ID Protection.