Toto does NOT include a wax ring with their toilets, but one IS required to seal the Unifit adapter to the flange, just like if it was a toilet. Nor do they include a hose to the fill valve. THen, the toilet sits on the adapter and is sealed by the rubber gasket so it is watertight the whole way.
Typical plumber...doesn't want to read the instructions, which are quite clear. If the floor has tile, he may not have a proper drill bit to anchor the adapter to the floor. This is CRUCIAL, since otherwise, the toilet will not be stable. Depending on the tile, it may work with a carbide bit, but a diamond core bit works on any hard surface. Some porcelain floor tile can be nearly as hard as diamonds, and carbide just won't cut it - literally. A but may wear it away, but you may go through more than one. A good diamond bit will slice through it quickly, as long as you keep the bit wet and don't press too hard.