1993 Acura Integra LS I heard knocking in the engine

I ran into your website and couldn't help myself telling you about my ordeal. I'd appreciate anything you can do to shed some light on this. Three weeks ago, I was driving at about 90-mph, when I heard knocking in the engine upon arrival to a toll. Since I've done my share of repairs on cars in the past, from replacing fuel pumps to bearings through the crank, I was almost certain it was a rod that lost either a bearing or something of the sort. I took it to the "experts" at Acura here in PR. They looked at it for about a day and they stated that it was just time for new bearings-all other components had sustained no damage due to my prompt reaction. I found it reasonable, so in went the new bearings - they called the next afternoon and said the car was ready. Arrived the next day, paid the $380 and wait for my car in an outdoor area. The Svc Supervisor went for my car, which was about 50 meters away. Immediately after starting the car, I heard the knock for about 1 second and he powered the car off and restarted, obviously, once the oil reached it, the knock quieted down. As he drove on, which in my opinion shouldn't have even happened, him being somewhat knowledgeable in this area, reached me; I mentioned that I heard it still knocking. He made a puzzled face and powered the car off/on again. I commented that it wasn't going to knock at startup again because oil had already lubricated the parts, but had him pop the hood where I pulled the throttle cable a little and the knocking became more louder. He and the Svc Manager insisted that it may be the timing belt at which time I paused to keep myself from falling. I asked him to pull the spark plug cable #2 where I heard most of the knocking; with the engine running and they were convinced that indeed the engine needed another look. Next day, I get a call from them stating that the crankshaft although passed all their initial tests the 1st time around with flying colors, now has irreparable damages that may need a replacement. [MSRP $980; $1000 in my book] Now it's costing me up to $900 in labor costs alone, plus $500 in parts that I've had to hunt down myself. Is there something I can claim or do about this in your perspective? I understand there's an ethic issue involved here, no. What tells me that in a month's time, my piston head won't warp or bend a valve? Are these components that should've been thoroughly checked before attempting client delivery?