July 2016 and I for one am having almost every problem mentioned in this thread. Also have tried berating them and firing and hiring other Sims. I always make sure they have high work ethic but it still does not make them ring up customers. At this point I just stopped hiring employees and struggle with my active Sim doing everything themselves-- which is made more annoying, as I mentioned elsewhere, by their getting lumped into group conversations when there are retail actions queued, and the retail actions either take forever to drop into the queue or simply get ignored.
I don't personally feel like the Sim working the retail store, or the employees, should be able to interact socially on their retail lot, period, outside of retail options if this whole thing about ending up in group conversations is going to keep on being a problem. I know in real life people do have casual conversations -- while they're ringing up or suggesting sales to the customers -- and some employees do indeed slack off instead of working properly, but it's just as realistic to have conversations while also ringing up/suggesting sales/cleaning. In other words, why do the regular social interactions supersede the retail actions to the point that no matter which employee, which active Sim or which retail lot you're on, you're still losing sale after sale?
Side question: when you have an employee perform a work task, do you need to tell them to do it again and again each time it needs doing, or does setting them that particular task once at the beginning of their shift mean they'll do it the whole time? I was wondering if perhaps that's why my employees wouldn't ring up customers when they were set to.