Looking for some help here. It's a collection of firsts for me - first post and first attempt at redeeming miles so hope I'm doing it right and in the right place! apologies in advance if I'm not.

I'm trying to use miles to send wife and daughter Gatwick to Orlando on Virgin UC, going out 15/10, coming back on 20/10. ANA tool shows availability, but when I called the call centre a (quite curt) gentleman told me all seats (in all classes) were taken pretty much a week each side of those dates. Can anyone help confirm if seats are available on those dates per ANA and, if so, how I can convince the call centre to give them to me

Cheers