For that price difference they are quoting different cars, did you give them your registration and VIN number?
I reckon one was with aircon and one was without. All quotes are taken off a centrally controlled system regulated by head office called rapidquote, two different cars are being compared here by the sound of it, not your fault though the service advisors.
Renault do charge more than independant garages, but then again their labour costs are more expensive. Often Renault garages seem expensive compared to other garages but thats because they use genuine renault parts. For example in a cambelt service the whole kit will be replaced including the tensioners. Cheaper back street garages and often the likes of kwik s**t etc will just change the belt with a non-genuine item as part of their cambelt service and won't touch the auxillary belts either. May as well not have bothered at all as its the tensioners that fail.
Its also worth bearing in mind that Renault service centres will price match other garages proving you are comparing like for like, i.e the other garages 36k service includes all the same genuine parts the 'Renault' 36k service does.
+ whatever on top needs replacing/fixing
