I am sorry that you sold your car because of these scammers but at least you did not pay them any money. I am sure if you had sent them the money, they would find another reason to ask for even more and keep going until you stop paying because tha tis how they work. Any lawyer that uses an email with a domain called popstars.com does not sound very trustworthy to me.
canadawantsyou.com looks more trustworthy with their own website but I looked them up on Better business bureau and found this: http://www.bbb.org/kitchener/business-reviews/immigration-and-naturalization-consultants/mcics-immigration-services-in-mississauga-on-1208114 It doesn't mean they are necessarily bad, just might not have been around very long.
In comparison, if you look up canadavisa.com, you get this: http://www.bbb.org/quebec/business-reviews/passport-and-visa-services/canadavisacom-in-westmount-qc-74
You should read the CIC fraud warning here: http://www.cic.gc.ca/english/information/protection/antifraud.asp