Service Tech ruined my computer/more

A tech came for warrantly service on my Dell 8950. all I needed was a new card reader. He replaced motherboard (necessary, evidently). After he left I noticed two external drives were not working, my B drive was evidently missing. I have been trying to deal with tech support since last Friday. I am out my machine, drives and years of data (local shop trying to recover any data). I am unable to connect with any English speaking person to get some help. I purchased a used machine to get me through until this mess can reach some sort of resolution, but I (once again) cannot reach anybody in this country (USA) to assist me. It is very obvious that Dell has a complicated system in place to prevent customers connecting with anyone who might help.