According to this website,which list the amenities of the (Occidental Allegro) Riviera Hotel,they do.
http://www.otbeach.com/cheap-holidays/tunisia/ town/port-el-kantaoui/hotel/occidental-allegro -riviera-295034.html?gclid=CO3K5_DvsJwCFUoB4wo dcidzkQ
However,it only list them as "Internet Services" it doesn't say exactly WHAT type of service is available,but it's a start.
In case you wonder what the name in brackets is (above) it's the full name of the hotel.Despite much Googling I cannot find the official website for the Riviera!
Correction!
Thanks to Zac's email addy,here is the official website of the Riviera Hotel:~
http://www.hotel-riviera-tunisie.com/index.php ?option=com_content&task=view&id=24&Itemid=32
If you click on the "extras" button you will see they list an "Internet Centre",so hopefully that should fill your needs!