Products / Services not shown if a client has a domain is his/her account

I created a few Products / Services in different groups. When a client start the process to buy a domain and select a package from the beginning, there is no problem and all the products are shown. When a client with a domain go to Services -> Order new services, the client can see the groups but they appear empty. What configuration am I missing to enable the possibility to show always the products.

Another question I have is: in a WHMCS working with a WHM/Cpannel server there is any way to delete an account from WHM and create a new one when a client purchase a different package?