Dont ever go this dealer i need to get diagnostic ...

Dont ever go this dealer i need to get diagnostic 2013 Chevy suburban LTZ my trunk problem to stuck to open automatic. I signed paper $142 per hourly i request one hour without notice they diagnostic 2 hour then they call me they said we cannot get the problem yet we need more hours to know the problem each hour is $142. I said stop. I paid $300 and non result. I recommend everyone please dont go or think. Chevy dealer in Bloomington. I hve 2013regular garages pera the price and expert these only the brand name Chevy