I'll try and make it short.
Did they mention anything about your cvi numbers? (clutch volume index) this can tell you the condition of the internals. This measurement basicly measures the volume /space of the fluid between the clutch's,this can indicate worn components. You need a scan tool, read the cvi values,if they are not in spec, you actuate a quick learn,(with a scan tool only) takes a couple minutes, but it basicly resets the transmission and lets the Pcm,tcm and trans learn together again. He might have not charged you anything because they could tell it was worn out inside and you will be back for a rebuild? disconnecting the battery resets the values and takes time to relearn, but if the reading are not at there predetermined value, or off the charts.No telling when or if it all matchs up again. hope all works out for you, Sometimes this is just a band aid fix.