Oil Sludge Problem

Hello,
Im new to this forum and I need your advice. I have a 2002 Passat 1.8 and I experienced the oil sludge problem. I bought it in 2005 and three months later the problem occured and I had to fight to get them to replace the valves to the engine without cost because it was under the recall. Since then the car has worked fine up until last week when the oil light and engine light came on again. Now they tell me that the engine and turbo needs to be replaced which will cost me $9600. Should I fight for them to fixe the engine without me paying for it? They told me that the engine went out because  I did not get the oil changes done in a timely manner. What do you think? Would getting proper oil changes have caused the engine to go out? I have 77,000 miles on it. 

 If your engine was full of sludge, then the oil hasn't been changed
 properly.or you may have a coolant leak, letting moisture enter
 the oil. if the sludge is dark like black then it's the oil not being
 changed properly, if it's mayonaise color then it's a coolant leak
 into the oil. Black sludge....owner's fault. light color sludge engine
 has a problem.   Black sludge will not happen if you change the
 oil, from 2000 to 3000 miles like you should. Black sludge, you
 don't have a leg to stand on in a battle for free repairs, even on
 a car with a warrantee wont get repaired free with black oil sludge.
  It's called owner neglect.
     SORRY FOR YOUR PROBLEM AND I DO WISH YOU
          GOOD LUCK

Hey I got lucky. I had low oil pressure and valves started knocking. I took my 02 passat to 3 different mechanics. I found one in Norwood, Ma. Auto Mall Service. He knew right away what was wrong. The screen in the oil pan was sludged out. The last owner didn't change oil every 2-3000 miles. With turbos you need to do this. Cost me $800.00 to replace screen because the engine needed to be lifted slightly to get to screen. I hope you are ok.