Illinois Truck Centre Unauthorized work scam Elk Grove Village Illinois

CONSUMERS BE AWARE, DON'T GO TO ILLINOIS TRUCK CENTRE
1-13-2016 I dropped off the truck for repair of oil leaking into radiator, and overflow tank.  Also the turn signals were not working properly.  
2-1-2016 I picked up the truck, paid $3949.17 for the repairs.  I got down the block and realized the truck was not fixed, and took it back.  The truck sat there for 4-5 weeks (into March).  They called and said they fixed it, and once again I took off, and it wasn't fixed.  I called them, and they said the problem would subside after I put some miles on the truck.
August 2016 I had put 280 miles on the truck since "they repaired it'.  Still had the same issues, and I had a 1 year warranty on the previous work, so I took it back.  The truck sat there through August, September, and into October and still there.  The only amount I authorized was $300.00 more for repair, nothing else.  
On October 6th, Wayne called, and left a voicemail saying "the parts, and labor" would be on his dime".
On October 10th, Wayne called, and said "a new oil pan would be on their dime".
On October 11th, I went to pick up the truck, and Wayne gave me a bill for $5944.00.  I told him I never authorized any work over $300.00.  Wayne stated "I assumed you wanted your truck fixed", and I stated "I would never authorize that amount".
The truck is a 2005 GMC, and the close to $10000.00 is more than the truck is worth.  He told me he would discuss this with the General Manager, and get back to me.  This never happened, as with many other times when phone calls were made to check on the status of the truck.  Wayne emailed once, and never returned any calls.  My wife has left numerous messages with no return.  A voicemail to Eugene was left, and he returned it by stating "he didn't listen to the voicemail but how can I help you?"  I explained what was going on, and he stated "I'll get back to you", and never did.  
Their customer service is HORRENDOUS, and what they've done is COMPLETELY UNACCEPTABLE!  

BOTTOM LINE: THEY DID UNAUTHORIZED WORK, AND WE'RE NOT PAYING FOR IT, AND THEY'RE HOLDING OUR TRUCK RANSOM.
WE'VE BOUGHT TWO TRUCKS FROM THEM BEFORE, AND THIS IS HOW THEY TREAT US.  
Read their reviews on social media, and you'll see this is not something new for them, they've done this before.  Obviously this is how they run their business.