After taking car to mechanic, still not fixed....sigh

What is your question?

My car would randomly stall (completely die) whether going slow or very fast on the highway. It was happening only once or twice every six months, but progressively got worse till it was like every other time I drove it. The garage had my vehicle for a week, replaced crankshaft position sensors, spark plugs, oil change and tire rotation for $836.00. It stalled two times driving it home. Called the garage, they said I could bring it in on monday, but they didn't sound like they were standing by their work or anything....they were not reassuring at all.....What is the best way for me to handle this? Thank you. (P.S. no current codes, only historical)