In the US, the WiFi has never been listed as a separate amenity on the invoice, since it is included in the cruise fare (1 with OLife and 2 with SM), as Lyn quotes above. I don't think it's your TA's choice not to give it to you since O provides it, but perhaps your TA is not totally familiar with O's marketing. Our TA provides us with an Oceania invoice, not an invoice from the agency, and WiFi is not explicitly shown, but we always get it for free.