"Olive oil" by nature (without even getting into fakes) has a fairly wide expected gamut -- extra virgin, virgin, refined, and pomace oils (all of which but the last can be marketed as unqualified "olive oil", though in practice that generally mean either refined or a blend of mostly refined and some virgin.)
A place that is doing something like artisanal premium extra virgin olive oil (which is what it sounds like you were getting) should have exactly the relation to generic "olive oil" that you describe, even if nothing involved is fake or adulterated in any way.
Which is not to say a lot of what you are buying as generic "olive oil" might not be fake (there's plenty of independent reason to suspect that), but what you describing doesn't really indicate that.
A place that is doing something like artisanal premium extra virgin olive oil (which is what it sounds like you were getting) should have exactly the relation to generic "olive oil" that you describe, even if nothing involved is fake or adulterated in any way.
Which is not to say a lot of what you are buying as generic "olive oil" might not be fake (there's plenty of independent reason to suspect that), but what you describing doesn't really indicate that.