Sounds like the steering shaft is disconnected from the rack and pinion assembly. Something else has to be going on because those parts are designed in such a way so that can't happen. The rack or the steering column has to be unbolted and physically moved to get the parts apart.
It's also possible for the inner tie rod bolts to come out but a lot of stuff has to go wrong there too. There's a plate with tabs that get bent over to hold the bolt heads from turning. The mechanic would have to forget to bend those tabs, then the bolts would have to work loose. You would have noticed a lot of knocking and felt it in the steering wheel long before those bolts came all the way out. Also, the chances of both bolts coming out at the same time is very unlikely.
That leaves the steering shaft as the main suspect. There is also a special bolt under the dash that may have come out. There is a cotter pin through the nut to prevent that. It too could have been forgotten. You're going to have to look to see what is turning and what isn't, then we can determine the best course of action. Be aware too that there is a clock spring under the steering wheel that is likely to be damaged. That is a wound-up ribbon cable in a plastic housing. It can only turn a little more than the steering system can before that cable gets tight and rips or it gets unwound too far and flips over on itself. Typically the steering wheel will turn about 1 1/2 turns either way from center to full turn. The clock spring can only go about 2 1/2 turns before it will be damaged. If you haven't turned the steering wheel too far yet, you might be able to save the clock spring.